nepal electricity authority · 2018-07-01 · tower spotting, optimization of tower locations soil...

NEPAL ELECTRICITY AUTHORITY (An Undertaking of Government of Nepal)

Project Management Directorate

KALIGANDAKI TRANSMISSION CORRIDOR PROJECT

BIDDING DOCUMENT FOR

Procurement of Plant

Design, Supply, Installation and Commissioning of New Butwal - Bardaghat 220 kV Double Circuit Transmission Line

Single-Stage, Two-Envelope

Bidding Procedure

Issued on: (29 June, 2018) Invitation for Bids No.: RE: ICB-PMD-KGTCP-073/074-02 ICB No.: RE: ICB-PMD/KGTCP/073/074-02 Employer: Nepal Electricity Authority Country: Nepal

VOLUME –II OF III

June 2018 Kaligandaki Transmission Corridor Project Project Management Directorate Satungal-Bauthali Chowk Marga, Chandragiri Municipality-11, Matatirtha Substation, Kathmandu, Nepal Telephone: +977-1-5164091, 5164177 Facsimile number: +977-1-5164099 Electronic mail address: [email protected]

Preface This Bidding Document for Procurement of Plant – Design, Supply, Installation and Commissioning has been prepared by Nepal Electricity Authority, Project Management Directorate, Kaligandaki Transmission Corridor Project and is based on the Standard Bidding Document for Procurement of Plant – Design, Supply, Installation and Installation (SBD Plant) issued by the Asian Development Bank (ADB) dated December 2016. ADB’s SBD Plant has the structure and the provisions of the Master Procurement Document entitled “Procurement of Plant – Design, Supply, Installation and Commissioning”, prepared by multilateral development banks and other public international financial institutions except where ADB-specific considerations have required a change.

TECHNICAL SPECIFICATION

FOR

220KV D/C NEW BUTWAL- BARDAGHAT TRANSMISSION LINE ASSOCIATED WITH

KALIGANDAKI CORRIDOR

VOLUME-II


(VOLUME-II)

CONTENTS

SECTION-I GENERAL INFORMATION & SCOPE

SECTION-II GENERAL TECHNICAL CONDITIONS

SECTION-III SURVEY AND SOIL INVESTIGATION

SECTION-IV TOWER, FOUNDATION, ERECTION, STRINGING AND COMMISSIONING OF LINE

SECTION-V CONDUCTOR

SECTION-VI INSULATOR

SECTION-VII HARDWARE FITTINGS & ACCESSORIES

SECTION-VIII GALVANISED STEEL EARTHWIRE

SECTION-IX OPGW

SECTION-X DRAWINGS

Bidding Document for RE: ICB-PMD-KGTCP-073/74-02: New Butwal – Bardaghat 220 kV Transmission Line (Design, Supply, Installation and Commissioning)

SECTION-I


SECTION-I

CONTENTS

Clause Description Page No.

1.0 General Information and Scope 1

2.0 Qualification Requirement for Contractor's Supplied Line Materials

7

3.0 Transmission towers & line data 14

4.0 Details of line materials 18

5.0 Service Conditions 20

6.0 Brief Summary of Major Changes 21


Section-I (TS) Volume-II Page 1 of 6

SECTION-I

TECHNICAL SPECIFICATIONS

1. General Information and Scope

1.1 Scope

1.1.1 The following transmission lines are included in the scope of the Contractor:

The line emanates from New Butwal Substation (Ramnagar), Nalwalparasi District and terminates to the dead end tower of Bharatpur - Bardghat 220 kV Transmission Line. Line named 220 kV D/C New Butwal - Bardaghat Transmission Line is of length 21 Kms.

1.1.2 This Specification covers the following scope of works:

(i) Detailed survey including route alignment, profiling, tower spotting, optimization of tower locations, soil resistivity measurement & geotechnical investigation (including special foundation locations viz. pile/well foundation locations, whenever applicable & covered under BPS);

(ii) Check survey;

(iii) Review of Design drawings of Towers and their foundations provided by the Employer and determine their suitability in the Project, do modification and produce new design if required ( the cost of design review, modification or production of new design deemed to be included in the Bidder’s offer)

(iv) Design of special towers, proto type testing, Fabrication and supply of all type of transmission line towers covered under BPS, including River crossing towers (wherever applicable) including fasteners, step bolts, hangers, D-shackles etc. ;

(v) Supply of all types of tower accessories like phase plate, circuit plate (where ever applicable), number plate, danger plate, anti-climbing device, Bird guard(where ever applicable);

(vi) Supply of

a) Earth wire, Hardware Fittings and Conductor & Earth wire Accessories

b) Conductor, Insulators

c) OPGW & associated fittings & accessories.

(vii) Design review of foundations provided by the Employer for different soil conditions for different type of towers covered under BPS, Classification of foundations for different type of tower and casting of foundations for tower footings as per approved foundations drawing;

(viii) Supply & Installation of Tower Earthing.

(ix) Erection of towers, tack welding of bolts and nuts including supply and application of zinc rich paint, fixing of insulator strings, stringing of conductors and earth wires/OPGW along with all necessary line accessories.



(x) Destringing & dismantling of existing 220/132/66kV Transmission line. (whenever applicable & covered under BPS)

(xi) Stringing of Power line crossing section under Live Line Condition (where ever applicable & covered under BPS);

(xii) Painting of towers & supply and erection of span markers, obstruction lights (wherever applicable) for aviation requirements (as required)

(xiii) Testing and commissioning of the erected transmission lines and

(xiv) Other items not specifically mentioned in this Specification and/or BPS but are required for the successful commissioning of the transmission line, unless specifically excluded in the Specification.

1.1.2.1 Contractor shall develop design of the special towers, structural drawings, shop drawings & Bill of Materials of all type of transmission line towers covered under BPS and carryout the proto testing of designed towers. Similarly, the design and drawings for all type of foundations for the towers shall also be developed by the contractor, in sequence, suiting the project requirement.

1.1.2.2 (a) The provisional quantities of fabricated & galvanized steel towers as per specifications requirement, foundation type and their numbers, quantity of various line materials and other items are given in appropriate Price Schedule in Volume-III of the bid documents. However, the work shall be executed as per approved construction drawings and project requirement.

(b) The various items of work are described very briefly in the appropriate Schedule of BPS. The various items of the BPS shall be read in conjunction with the corresponding sections in the Technical Specifications including amendments and, additions, if any. The Bidder’s quoted rates shall be based on the description of activities in the BPS as well as other necessary operations required to complete the works detailed in these Technical Specifications.

(c) The Unit rates quoted shall include minor details which are obviously and fairly intended, and which may not have been included in these documents but are essential for the satisfactory completion of the various works.

(d) The unit rate quoted shall be inclusive of all plant equipment, men, material skilled and unskilled labour etc. essential for satisfactory completion of various works.

(e) All measurements for payment shall be in S.I. units, lengths shall be measured in meters corrected to two decimal places. Areas shall be computed in square meters & volume in cubic meters, rounded off to two decimals.

1.1.2.3 The Bidder shall quote the unit rates for tower and foundation as per units mentioned in appropriate price schedules. However, payment of these items identified in the schedule of prices shall be made as follows:



Tower Supply : On completion of respective complete tower

Tower Erection : On erection of respective complete tower

Tower Foundation : On completion of respective foundation in all respect

1.1.3 This specification also includes the supply of the following items, as detailed in the specification.

(a) Earth wire & hardware fittings and all type of accessories for conductor and earth wire.

(b) Insulator & Conductor

(c) OPGW & associated fittings and accessories

Contractor shall clearly indicate in their offer, the sources from where they propose to procure these materials in appropriate Schedule of BPS. The technical descriptions of these items are given in relevant sections of this Volume

1.1.4 All the raw materials such as steel, zinc for galvanizing, reinforcement steel and cement for tower foundation, coke and salt for tower earthing etc. bolts, nuts, washers, step bolts, D-shackles, hangers, links, danger plates, phase plates , number plates, Circuit Plates, aviation signals etc., required for tower manufacture and erection shall be included in the Contractor’s scope of supply. Bidder shall indicate in the offer, the sources from where they propose to procure the raw materials and the components.

1.1.5 The casting of special pile/well foundations, wherever required shall be in the scope of the Bidder as per the approved drawings. If the bidder does not have necessary experience and is not meeting the qualifying requirements, some other agencies meeting the qualifying requirements may be engaged by the bidder for the casting of pile/well foundations.

or

In case of special type pile or well foundations, some other contractor may be engaged by the Employer for casting of foundations. However, the Bidder shall be responsible for all the necessary co-ordination with the special foundation Contractor including stub-setting/fixing of base plate with anchor bolt.

1.2 Details of Transmission Line Routes and Terrain

Detailed survey including route alignment and profiling have been carried out by the Owner and these are not expected to vary substantially. The contractor has to carry out the tower spotting, optimization of tower locations, soil resistivity measurement & geotechnical investigation etc.



However, certain quantity of detailed survey including route alignment, profiling, tower spotting, optimization of tower locations soil resistivity measurement & geotechnical investigation etc. have been kept in the scope of the contractor for changes in the route, if any, necessitated during execution stage.

The details collected through detailed survey viz, route alignment maps, detailed survey reports etc. are enclosed with this specification. Head loading may be required at certain locations. Bidders may visit the line route to acquaint themselves with terrain conditions and associated details of the proposed transmission lines.

1.3 Location Details and Terminal Points –

1.3.1 The 220kV New Butwal- Bardaghat transmission line shall emanate from New Butwal substation/switchyard at Surya Basti, Sunawal Municipality, Ward no. 14 of Nawalparasi district and terminate at the dead end tower of Bharatpur Bardaghat 220 kV Transmission Line near Bardaghat substation at Bidyut tole, Bardaghat Municipality Ward no. 4 of Nawalparasi district

The transmission line is passing mostly through Plain and some hilly area.

1.3.2 The Contractor shall have to construct these transmission lines completely up to dead end towers on either end. Stringing shall also be carried out from dead end tower to terminal arrangements/terminal points.

1.4 Access to the Line and Right of Way

Right of way and way leave clearance shall be arranged by the Employer in accordance with work schedules. Employer will secure way leave and Right of way in the Forest area.

1.5 Contractor Execution Plan

After award of the contract, the contractor shall submit a detailed plan for resources mobilization & execution of various activities under the project. The detail should also cover the locations and size of stores to be established by the contractor.

The contractor shall deploy a Project Manager at site who shall not be allowed to be changed without the consent from NEA, once deployed. The work at site shall be carried out after permission from the Site-in-charge and with proper consent of land owners and forest officials.

2.1 Electrical System Data

2.1.1 220 kV transmission line

1. 1. Nominal Voltage kV 220

2. Maximum system voltage kV 245

3. BIL (Impulse) kV (Peak) 1050



4. Power frequency withstand voltage (Wet)

kV (rms) 460

5. Minimum Corona extinction voltage at 50 Hz AC system under dry condition

kV (rms) phase to earth.

154 (Min)

6. Radio interference voltage at one MHz for phase to earth voltage of 154 KV under dry condition.

Micro Volts 1000 (Max)

3.0 Details of line Materials

3.1 220 kV Double Circuit transmission line

3.1.1 Details of Conductor & Earthwire

Sl. No.

Description Conductor Earthwire OPGW

1. Type ACSR ‘BISON’ conductor

7/3.35mm GS Earthwire

Equivalent to 7/3.35 mm GS Earthwire

2. Stranding and wire diameter

Aluminium / Al Alloy 54/3.0 -

Steel 7/3.0 7/3.35

3. Conductor per phase 2 NA

4. Spacing between conductor of same phase(mm)

450 NA

5. Overall Diameter (mm) 27 10.05

6. Unit mass (kg/km) 1444 483

7. Min. UTS (kN) 117.5 61.1

8. Configuration Vertical One continuously to run horizontally on top of the towers and conductors.

One continuously to run horizontally on top of the towers &

conductors.

3.1.2 Details of insulator strings with standard disc/ composite long rod insulators.

Sl.

No.

Type of string *No of

disc

insulators

*No. of

composite

long rod units

Electro-mechanical

strength of insulator

disc/ composite

longrod (KN)

Mechanical strength of

insulator string along

with hardware fittings

(KN)

1. Single ‘I’ suspension

1X14 1X 1 70 70

2. Single ‘I’ suspension Pilot

1x14 1x1 70 70

3. Double tension 2x15 2x1 120 2X 120



4.0 Service Conditions:

Equipment/material to be supplied against this specification shall be suitable for satisfactory continuous operation under tropical conditions as specified below:

Maximum ambient temperature (Degree Celsius) : 45

Minimum ambient temperature (Degree Celsius) : 0

Relative humidity (% range) : 10-100

Wind zone (as per IS: 875) : 4

Maximum wind velocity (m/sec.) : 47

Maximum altitude above mean sea level (Meters) : 1000

Isoceraunic level (days/years) : 60

Moderately hot and humid tropical climate conducive to rust and fungus growth.


Section-II Volume – II

1


SECTION - II

GENERAL TECHNICAL CONDITIONS

1.1 General

The following provisions shall supplement all the detailed technical specifications and requirements brought out herein. The contractor’s proposal shall be based on the use of materials complying fully with the requirements specified herein.

1.2 Engineering Data

1.2.1 The furnishing of engineering data by the Contractor shall be in accordance with the Schedule as specified in the Bidding Document. The review of these data by the Employer will cover only general conformance of the data to the specifications and not a through review of all dimensions, quantities and details of the materials, or items indicated or the accuracy of the information submitted. This review by the Employer shall not be considered by the Contractor, as limiting any of his responsibilities and liabilities for mistakes and deviations from the requirements, specified under these specifications.

1.2.2 All engineering data submitted by the Contractor after review by the Employer shall form part of the contract document.

1.3 Drawings

In addition to those stipulated in clause regarding drawings in GCC/SCC, the following also shall apply in respect of Contractor Drawings.

1.3.1 All drawings submitted by the Contractor including those submitted at the time of Bid shall be with sufficient detail to indicate the type, size, arrangement, dimensions, material description, Bill of Materials, weight of each component break-up for packing and shipment, fixing arrangement required, the dimensions required for installation and any other information specifically requested in these specifications.

1.3.2 Each drawing submitted by the Contractor shall be clearly marked with the name of the Employer, the specification title, the specification number and the name of the Project. All titles, noting, markings and writings on the drawing shall be in English. All the dimensions should be to the scale and in S.I. units.

1.3.3 The drawings submitted by the Contractor shall be reviewed by the Employer as far as practicable within 28 days and shall be modified by the Contractor if any modifications and/or corrections are required by the Employer. The Contractor



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shall incorporate such modifications and/or corrections and submit the final drawings for approval. Any delays arising out of failure by the Contractor to rectify the drawings in good time shall not alter the contract completion date.

1.3.4 The drawings submitted for approval to the Employer shall be in quadruplicate. One print of such drawings shall be returned to the Contractor by the Employer marked “approved/approved with corrections”. The contractor shall there upon furnish the Employer additional prints as may be required along with one reproducible in original of the drawings after incorporating all corrections.

1.3.5 The work shall be performed by the Contractor strictly in accordance with these drawings and no deviation shall be permitted without the written approval of the Employer, if so required.

1.3.6 All manufacturing, fabrication and erection work under the scope of Contractor, prior to the approval of the drawings shall be at the Contractor’s risk. The contractor may incorporate any changes in the design, which are necessary to conform to the provisions and intent of the contract and such changes will again be subject to approval by the Employer.

1.3.7 The approval of the documents and drawings by the Employer shall mean that the Employer is satisfied that:

(a) The Contractor has completed the part of the Works covered by the subject document (i.e. confirmation of progress of work).

(b) The Works appear to comply with requirements of Specifications.

In no case the approval by the Employer of any document does imply compliance with technical requirements nor the absence of errors in such documents.

If errors are discovered any time during the validity of the contract, then the Contractor shall be responsible for consequences.

1.3.8 All drawings shall be prepared using AutoCAD software version 2000 or later only. Drawings, which are not compatible to AutoCAD software version 2000 or later, shall not be acceptable. After final approval all the drawings shall be submitted to the Employer in AutoCAD or other compatible version (in editable format) in CDs.

A copy of each drawing reviewed will be returned to the Contractor as stipulated herein.

1.3.9 Copies of drawings returned to the Contractor will be in the form of a print with the Employer’s marking, or a print made from a microfilm of the marked up drawing.



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1.3.10 The following is the general list of the documents and drawings that are to be approved by the Employer.

a) Work Schedule (Master Network) Plan.

b) Detailed survey report and profile drawings showing ground clearance and tower locations (as applicable).

c) Tower schedule and foundation classification for individual tower locations (as applicable).

d) Tower structural drawing and bill of materials.

e) Soil Investigation report.

f) Foundation working drawings/excavation Plan.

g) Tower footing earthing drawing.

h) Stub and stub-setting template drawings.

i) Stringing procedure and stringing chart.

j) Tower accessories drawings like danger plate, name plate etc.

k) Quality plans for fabrication and site activities including Quality System.

l) Sub-vendors approval, etc.

m) Line material drawings.

n) Type test report for line materials.

1.3.11 All rights of the design/drawing for all types of towers and foundations shall be strictly reserved with the Employer only and any designs/drawings/data sheets submitted by the contractor from time to time shall become the property of the Employer. Under no circumstances, the Contractor shall be allowed to use/offer above designs/drawings/data sheets to any other authority without prior written permission of the Employer. Any deviation to above is not acceptable and may be a cause for rejection of the bid.

1.4 Design Improvements

1.4.1 The Employer or the Contractor may propose changes in the specification and if the parties agree upon any such changes and the cost implication, the specification shall be modified accordingly.



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1.5 Design Co-ordination

Wherever, the design is in the scope of Contractor, the Contractor shall be responsible for the selection and design of appropriate material/item to provide the best co-coordinated performance of the entire system. The basic design requirements are detailed out in this Specification.

The design of various components, sub-assemblies and assemblies shall be so done that it facilitates easy field assembly and maintenance.

1.6 Design Review Meeting

The contractor will be called upon to attend design review meetings with the Employer, and the consultants of the Employer during the period of Contract. The contractor shall attend such meetings at his own cost at the Corporate Office of the Employer or at mutually agreed venue as and when required. Such review meeting will be held generally four times in a year.

1.7 Quality Assurance, Inspection & Testing

1.7.1 Quality Assurance

To ensure that the supply and services under the scope of this Contract whether manufactured or performed within the Contractor’s works or at his Sub-Contractor’s premises or at site or at any other place of work are in accordance with the specifications. The Contractor shall adopt suitable quality assurance programme to control such activities at all points necessary. Such programme shall be broadly outlined by the Contractor and shall be finalised after discussions before the award of Contract. The detailed programme shall be submitted by the contractor after the award of contract and finally accepted by the Employer after discussion. A quality assurance programme of the Contractor shall generally cover but not limited to the following:

(a) His organisation structure for the management and implementation of the proposed quality assurance programme.

(b) Documentation control System.

(c) Qualification data for Contractor’s key personnel.

(d) The procedure for purchase of materials, parts components and selection of sub-Contractor’s services including vendor analysis, source inspection, incoming raw material inspection, verification of material purchases etc.

(e) System for shop manufacturing including process controls and fabrication and assembly controls.

(f) Control of non-conforming items and system for corrective action.



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(g) Control of calibration and testing of measuring and testing equipments.

(h) Inspection and test procedure for manufacture.

(i) System for indication and appraisal of inspection status.

(j) System for quality audits.

(k) System for authorising release of manufactured product to the Employer.

(l) System for maintenance of records.

(m) System for handling storage and delivery and

(n) A quality plan detailing out the specific quality control procedure adopted for controlling the quality characteristics relevant to critical and important items of supply.

The Quality plan shall be mutually discussed and approved by the Employer after incorporating necessary corrections by the Contractor as may be required.

1.7.1.1 Quality Assurance Documents

The Contractor shall be required to submit all the Quality Assurance Documents as stipulated in the Quality Plan at the time of Employer's inspection of equipment/material.

1.7.1.2 The Employer or his duly authorised representatives reserves the right to carry out Quality Audit and quality surveillance of the systems and procedures of the Contractor's/his vendor's Quality Management and Control Activities.

1.7.2 Employer's Supervision

1.7.2.1 To eliminate delays and avoid disputes and litigation to the Contract, all matters and questions shall be resolved in accordance with the provisions of this document.

1.7.2.2 The manufacturing of the product shall be carried out in accordance with the specifications. The scope of the duties of the Employer, pursuant to the contract, will include but not be limited to the following.

a) Interpretation of all the terms and conditions of these Documents and Specifications.

b) Review and interpretation of all the Contractor's drawings, engineering data etc.

c) Witness or authorise his representative to witness tests at the manufacturer's works or at site, or at any place where work is performed under the contract.



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d) Inspect, accept or reject any equipment, material and work under the Contract, in accordance with the Specifications.

e) Issue certificate of acceptance and/or progressive payment and final payment certificate.

f) Review and suggest modification and improvement in completion schedules from time to time, and

g) Supervise the Quality Assurance Programme implementation at all stages of the works.

1.7.3 Inspection & Inspection Certificate

1.7.3.1 The Employer, his duly authorized representative and/or outside inspection agency acting on behalf of the Employer shall have, at all reasonable times, access to the premises and /or works of the contractor and/or their sub-contractor(s)/sub-vendors and shall have the right, at all reasonable times, to inspect and examine the materials and workmanship of the product during its manufacture.

1.7.3.2 The Contractor shall give the Employer's Inspector fifteen (15) days (in case of domestic testing and thirty (30) days (in case of foreign testing), as the case may be, written notice of any material being ready for testing. In case of turnkey contract, the turnkey contractor shall give the notice for inspection and shall associate in the inspection with Employee’s inspector. All such inspections shall be to the Contractor's account except for the expenses of the Employer’s inspector. The Employer’s inspector, unless witnessing of the tests is virtually waived, will attend such tests within fifteen (15) days (in case of domestic testing) and thirty (30) days in (in case of foreign testing) of the date of which the equipment is notified as being ready for test/inspection or on a mutually agreed date, failing which the Contractor may proceed with the test which shall be deemed to have been made in the inspector's presence and he shall forthwith forward to the inspector duly certified copies of test reports / certificates in triplicate.

1.7.3.3 The Employer’s Inspector shall, within fifteen (15) days from the date of inspection, give notice in writing to the Contractor, of any objection to any drawings and all or any equipment and workmanship which in his opinion is not in accordance with the Contract. The Contractor shall give due consideration to such objections and shall make the modifications that may be necessary to meet the said objections.

1.7.3.4 When the factory tests have been completed at the Contractor’s or Sub-Contractor’s works, the Employer’s inspector shall issue a certificate to this effect within fifteen (15) days after completion of tests but if the tests are not



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witnessed by the Employer’s inspector, the certificate shall be issued within fifteen (15) days of receipt of the Contractor’s Test Certificate by the Employer’s Inspector. The completion of these tests or the issue of the certificate shall not bind the Employer to accept the equipment should it, on further tests after erection, be found not to comply with the Contract.

1.7.3.5 In all cases where the Contract provides for test whether at the premises or works of, the Contractor or of any Sub-Contractor, the Contractor except where otherwise specified shall provide free of charge such item as labour, materials, electricity, fuel, water, stores, apparatus and instruments as may be reasonably demanded by the Employer’s inspector or his authorised representative to carry out effectively such tests of the equipment in accordance with the Contract and shall give facilities to the Employer’s Inspector or to his authorised representative to accomplish testing.

1.7.3.6 The inspection by Employer and issue of Inspection Certificate thereon shall in no way limit the liabilities and responsibilities of the Contractor in respect of the agreed Quality Assurance Programme forming a part of the Contract.

1.7.3.7 a) The Contractor shall keep the Employer informed in advance about the time of starting and of the progress of manufacture and fabrication of various parts at various stages, so that arrangements could be made for inspection.

b) The acceptance of any part of items shall in no way relieve the Contractor of any part of his responsibility for meeting all the requirements of the Specifications.

1.7.3.8 The Employer or his representative shall have free access at all reasonable times to those parts of the Contractor’s works which are concerned with the fabrication of the Employer’s material for satisfying him that the fabrication is being done in accordance with the provisions of the Specifications.

1.7.3.9 Unless specified otherwise, inspection shall be made at the place of manufacture prior to dispatch and shall be concluded so as not to interfere unnecessarily with the operation of the work.

1.7.3.10 Should any member of the structure be found not to comply with the supplied design, it shall be liable to rejection. No member once rejected shall be resubmitted for inspection, except in cases where the Employer or his authorised representative considers that the defects can be rectified.

1.7.3.11 Defect which may appear during fabrication shall be made good with the consent of, and according to the procedure proposed by the Contractor and approved by the Employer.

1.7.3.12 All gauges and templates necessary to satisfy the Employer shall be supplied by the contractor.



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1.7.3.13 The specified grade and quality of steel shall be used by the Contractor. To ascertain the quality of steel used, the inspector may at his discretion get the material tested at an approved laboratory.

1.7.4 Tests and Standards

1.7.4.1 Tests

The type, acceptance and routine tests and tests during manufacture shall be carried-out on the material and shall mean as follows:

1.7.4.1.1 Type Tests shall mean those tests which are to be carried out to prove the process of manufacture and general conformity of the material to this Specification. These tests shall be carried out on samples prior to commencement of commercial production against the order. The Bidder shall indicate his schedule for carrying out these tests.

1.7.4.1.2 Acceptance Tests shall mean those tests which are to be carried out on samples taken from each lot offered for pre-dispatch inspection, for the purposes of acceptance of that lot.

1.7.4.1.3 Routine Tests shall mean those tests, which are to be carried out on the material to check requirements which are likely to vary during production.

1.7.4.1.4 Tests during manufacture shall mean those tests, which are to be carried out during the process of manufacture and end inspection by the Contractor to ensure the desired quality of the end product to be supplied by him.

1.7.4.1.5 The norms and procedure of sampling for these tests will be as per the Quality Assurance Programme to be mutually agreed to by the Contractor and the Employer.

1.7.4.1.6 The standards and norms to which these tests will be carried out are listed against them. Where a particular test is a specific requirement of this Specification, the norms and procedure of the test shall be as specified in Annexure-A or as mutually agreed to between the Contractor and the Employer in the Quality Assurance Programme.

1.7.4.1.7 For all type and acceptance tests, the acceptance values shall be the values specified in this Specification or guaranteed by the Bidder, as applicable.

1.7.4.2 Standards

The Codes and/or standards referred to in the specifications shall govern, in all cases wherever such references are made. In case of a conflict between such



9

codes and/or standards and the specifications, the latter shall govern. Such codes and/or standards, referred to shall mean the latest revisions, amendments/changes adopted and published by the relevant agencies unless otherwise specified.

1.7.4.2.1 Other internationally accepted standards which ensure equal or better performance than those specified shall also be accepted, subject to prior approval by the *Owner/*Employer/*Employer.

1.7.4.2.2 The standards are available from

Reference/Abbreviation Name and address from which the Standards/guides are available

IS Bureau of Indian Standards

Manak Bhawan, 9, Bahadur Shah Zafar Marg, New Delhi India.

ISO International Organisation for Standardisation, Danish Board for Standardisation, Dansk Standardising Sraat, Aurehoegvei-12 DK-2900 Hellepruip, DENMARK

CSA Canadian Standard Association 178,Rexadale Boulevard, Rexdale(Ontario) Canada M9W 1R3

DIN Deutsches Institute Fiir Normung Burggrafenstrassee 4-10 Post Fach 1107 D-1000, Berlin-30 GERMANY

ASTM American Society for Testing and Material 1916 Race Street Philadelphia.PA 19103-1187 USA



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Indian Electricity Rules Kitab Mahal Regulation for Baba Kharak Singh Marg Crossing New Delhi-110001 of Railway Tracks INDIA

ASCE American Society of Civil Engineers 345 East 47th Street New York, NY 10017-2398 USA

IEEE Institute of Electrical and Electronics Engineers 445 Hoes Lane Piscataway, NJ 0085-1331 USA

IEC International Electrotechnical Commission Bureau Central de la Commission 1 rue, de varembe, Geneva Switzerland.

1.8 Standard Technical Particulars

1.8.1 The Standard Technical Particulars of the various items are given in the relevant schedule of the specification. The bidder is required to comply with the same.

1.9 Packing

1.9.1 All the materials manufactured at the manufacturer's works shall be labeled "NB220KV/NB" before the inspection is being carried out.

1.9.2 All the materials shall be suitably protected, coated, covered or boxed and crated to prevent damage or deterioration during transit, handling and storage at Site till the time of erection. The Contractor shall be responsible for any loss or damage during transportation, handling and storage due to improper packing.

1.9.3 The Contractor shall include and provide for securely protecting and packing the materials so as to avoid loss or damage during transport by air, sea, rail and road.

1.9.4 All packing shall allow for easy removal and checking at site. Wherever necessary, proper arrangement for attaching slings for lifting shall be provided. All packages shall be clearly marked for with signs showing ‘up’ and ‘down’ on the sides of boxes, and handling and unpacking instructions as considered



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necessary. Special precaution shall be taken to prevent rusting of steel and iron parts during transit by sea.

1.9.5 The cases containing easily damageable material shall be very carefully packed and marked with appropriate caution symbols, i.e. fragile, handle with care, use no hook etc. wherever applicable.

1.9.6 Each package shall be legibly marked by the Contractor at his expenses showing the details such as description and quantity of contents, the name of the consignee and address, the gross and net weights of the package, the name of the Contractor etc.

1.9.7 Angle section shall be wire bundled.

1.9.8 Cleat angles, gusset plates, brackets, fillet plate, hanger and similar loose pieces shall be tested and bolted together in multiples or securely wired through holes.

1.9.9 Bolts, nuts washers and other attachments shall be packed in double gunny bags accurately tagged in accordance with the contents.

1.9.10 The packing shall be properly done to avoid losses & damages during transit. Each bundle or package shall be appropriately marked.

1.10 Storage of Material

Brief guidelines for storage of different type of construction material used in the transmission line projects are as under:

1.10.1 Cement Storage

Cement received at site should be stored in a building or shed which is dry, leak proof and moisture proof. The building should have minimum numbers of windows. Cement bags stored and stacked off the floor on wooden planks in such a way so as to keep about 150 mm to 200 mm clearance from the ground. The floor may be of lean cement concrete or two layers of dry bricks laid on well consolidated earth. A minimum space of 600 mm shall be kept around and between the exterior walls and the stacks. In stacks, bags shall be kept close together to reduce air circulation. The height of the stack shall not be more than 12 bags and the width of the stack shall not be more than four bags or 3 meters. For extra safety during monsoon, or when it is expected to store for an unusually long period, the stack shall be completely enclosed by a waterproofing membrane such as polyethylene etc. Different type and make of cement shall be stacked and stored separately.

1.10.2 Aggregates

Aggregates shall be stored at site on a hard dry and level patch of ground. If such a surface is not available, a platform of planks or old corrugated iron sheets, or



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floor bricks or a thin layer of lean concrete shall be made so as to prevent contamination with clay, dust, vegetable and other foreign matter.

The stacks of fine and coarse aggregates shall be kept in separate stock piles sufficiently removed from each other to prevent the material at the edges of the piles from getting intermixed. Fine aggregate shall be stacked in a place where loss due to the effect of wind is minimum.

1.10.3 Reinforcement Steel

For each classification of steel, separate areas shall be earmarked. It is desirable that ends of bars and sections of each class be painted in distinct separate colors. Steel reinforcement shall be stored in such a way as to avoid distortion and to prevent deterioration and corrosion. It is desirable to coat reinforcement with cement wash before stacking to prevent scaling and rusting in case of storage time exceeding one month. In store, reinforcement bars shall be stacked above ground level by at least 150 mm either on brick/cement/stone platform or concrete/bricks planks.

1.10.4 Structural Steel or Tower Parts

The structural steer of different classification, sizes and lengths shall be stored separately. These shall be stored above ground level at least 150 mm upon platforms, skids or any other suitable supports to avoid any distortion of sections. Also, in order to prevent white rust formation sufficient care should be exercised while storing, handling and transporting galvanized products. The structural steel/tower parts shall be stored in an adequately ventilated area. The article shall be stored with spacers in between them and kept at an inclination to facilitate easy drainage of any water collected on the structural steel/tower parts.

1.10.5 Conductor & Earthwire Drums

It is essential to save the conductor drums from damage during storage and transportation and the wooden battens and main wheel should be intact so that same can be successfully mounted on the conductor jacks to release the conductor during stringing. All the conductor and earthwire drums should be stored on a proper hard platform above ground to avoid deterioration of the drum and further avoiding the damage of conductor. The conductor & earthwire drums should be stored in such a manner that each drum can be accessed at any time for inspection purposes.

1.10.6 Hardware fitting, Accessories & Insulators

All the hardware fittings, accessories and insulators should be stored on raised platform above ground so as not to damage the packaging and to avoid further damage or denting on the fittings and chipping of insulators. All the aluminum



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parts should be stored on a plain/raised platform under a cover shed in such a way that the aluminum fittings cannot be distorted during storage..

2.0 Environmental Mitigation Measures 2.1 Physical Environment The following mitigation measures shall be undertaken to reduce the adverse

impacts on the physical environment during construction of the transmission line.

1. Discharge of cement slurry, garbage and other solid wastes generated by the construction activities and workforce should be avoided where possible.

2. Chemical and other hazardous materials should be dumped safely far away from the water bodies.

3. Disposal material of substation should be carried out within the acquired land for substation. The waste materials of the substation shall be minimized to avoid separate land for disposal.

2.2 Biological Environment

None

2.3 Socio-economic and cultural Environment In the construction phase following mitigation measures shall be adopted in

accordance with the EIA final report to minimize the impacts:

Control of adverse socio interactions between local communities and construction work force.

Awareness program regarding health and safety of transmission line.

Awareness program for workforce.

Insurance against health and safety.

2.4 Employment

The job preferences shall be given to local project affected family people. 3.0 Trainings 3.1 Training to be imparted abroad The following trainings shall be conducted in a Country of the Bidder or another

country, which shall be decided during the Contract Negotiations.



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1. Training on Applicable standards and codes for Transmission Line including IEC, IS & BS including supply of one set of ALL APPLICABLE STANDARDS for the EMPLOYER : A complete set of all applicable standards mentioned in the Bidding Document shall be delivered to the Employer immediately after the Contract Agreement is reached. A training shall be provided to 6 trainees for a duration of 10 days immediately after Contract Agreement to refresh the Employer regarding the applicable standards that shall be exercised during the implementation of the Project. The bidder shall have to bear the per diem expenses of the participants at the rate of USD 300 per day per participants and the Air Fare and accommodation. The training shall be brief and calculations in Excel formats shall be provided to the trainees so that they can use them further during checks and approvals of the designs and drawing that shall be submitted by the Contractor during the course of execution of Contract.

3.2 Training to be imparted in Nepal Bidders are required to impart 3 training modules to be conducted in Nepal.

Bidders are required to quote for the same in the corresponding Price Schedule. Though the Training shall have mainly Electrical Engineers as participants, some Civil Engineers shall also participate. The Bidder shall consider induction of basic concepts of both Civil and Electrical Engineering to groom the participants to specialize them for Transmission Line Engineering. The Bidder shall pay the participants an allowance of NRs. 1000.00 per day per participant.

The training may be split in two phases for other participants apart from Project Engineers. This will be an on the job training. Location and timing of the training shall be decided during Contract Negotiations.

The bidder shall use the relevant software during the training period. The Bidder shall also consider cost of software during the period of training to the participants if they do not have the software.

The following trainings shall be undertaken during the initial period of Contract

Execution with a view that the design shall be carried out by the Bidder in Nepal and all trainees participate in the design of the towers to be used for the Scope of the Project.

1. Structural design of Electrical Transmission Tower using conventional design

method as well as using PLS Tower for Electrical Engineers 2. Foundation Design for Electrical Engineer 3. TL design using PLS CADD including coding and decoding of .wir files for Electrical

Engineers.


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SECTION- 3

DETAILED SURVEY AND SOIL INVESTIGATION

1.0 Detailed Survey, Optimization of Tower Location

1.1 Detailed survey along the route alignment has been carried out and profile has been plotted on the drawings by the Employer. Details of angle of deviation and section lengths along with route alignment drawings have been given. The Contractor shall have to do tower spotting on already prepared profile drawings, optimize tower locations and carry out the check survey for the total length of transmission line. Tower spotting, optimization of tower locations and check survey shall have to be carried out by the Contractor in line with the provision stated in Clause 1.2 of Section – 1 of this Specification.

1.2 The Provisional quantity for detailed survey & check survey has been indicated in Price Schedule. The final quantity for the detailed survey shall be the route length along the revised route alignment, if any, and final quantity of check survey shall be the route length along the final route alignment. The tower spotting and optimization of tower locations shall be carried out by the Contractor on the basis of approved Tower Spotting Data preferably using PLS-CADD software.

1.3 The Contractor shall submit the proposal for detailed survey , in case of change (if necessary) in the present route alignment finalized by the Employer and shall carry out the detailed survey, profiling & optimization of tower locations only after getting approval from the Employer. The decision of Employer in this regard shall be final and binding for the Contractor. The Contractor shall finalize and submit results of detailed survey including changes suggested within the time schedule identified for completion of check survey and as agreed at the time of award. The soil investigation for the obligatory points are to be carried out by the Contractor as detailed out in this specification.

1.3 The Contractor should note that Employer will not furnish the topographical maps but will make available any assistance that may be required in obtaining the topographical maps.

1.4 The check survey shall be made along the approved route alignment after finalizing the detailed survey.

1.5 Soil resistivity along the route alignment shall be measured in dry weather by four-electrode method keeping inter-electrode spacing of 50 meters. For calculating soil resistivity formula 2πar (where a=50 meters and r = megger reading in ohms) shall be adopted. Measurement shall be made at every 2 to 3 kms along the route of transmission lines. In case soil characteristic, changes within 2 to 3 kms., the value shall also have to be measured at intermediate


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locations. The megger reading and soil characteristics shall also be indicated in the soil resistivity results.

1.6 Detailed Survey

Following activities shall be part of Detailed Survey work:

1.6.1 Route Marking

At the starting point of the commencement of route marking for detailed survey an angle iron spike of 65x65x6mm section and 1000mm long shall be driven firmly into the ground to project only 150 mm above the ground level. A punch mark on the top section of the angle iron shall be made to indicate location of the survey instrument.

All angle positions and terminal points shall be marked with concrete pillars and all intermediate points should also be marked with concrete pillars a interval not more than 300 meters. The concrete pillars of minimum 100x100x600 mm in size with NEA marked on them shall be embedded into the ground for easy identification. The concrete pillars shall be embedded firmly into the ground to project 150 mm only above ground level.

1.6.2 Profile Plotting & Tower Spotting

From the field book entries, the route plan with route details and level profile shall be plotted and prepared to scale of 1:2000 horizontal & 1:400 vertical on the paper having grid of 10mmX10mm as per approved procedure. Reference levels at every 20 meters along the profile are also to be indicated on the profile besides, R/Ls at undulations. Areas along the profile sheet, in the view of the contractor, are not suitable for tower spotting, shall also be clearly marked on the profile plots. If the difference in levels be too high, the chart may be broken up accordingly to requirement. A 10mm overlap shall be shown on each following sheet. The chart shall progress from left to right having width of Sheet 594 mm wide. For ‘as built’ profile these shall be in A1 size.

1.7 Spotting of Tower Location

1.7.1 Sag Template & Tower Spotting Data

Sag - tension calculation for conductor & earth wire and other necessary data (ground clearance, permissible sag error etc.) are provided with the bid. On basis of these, the Contractor shall prepare the Sag template curve drawing and Tower Spotting Data and shall submit the same along with sag –tension calculations for the approval of the Employer. Sag template prepared based on the approved sag-template curve drawing shall only be used for tower spotting on the profiles. Two numbers of the approved template, prepared on rigid transparent plastic sheet, shall be provided by the Contractor to the Employer for the purpose of


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checking the tower spotting. The templates shall be on the same scale as that of the profile.

1.7.2 Tower Spotting

With the help of approved sag template and tower spotting data, tower locations shall be marked on the profiles. While locating the towers on the profile sheet, the following shall be borne in mind:

(a) Span

The number of consecutive spans between the section points shall not exceed 15 spans or 5 Km in plain terrain and 10 spans or 3km in hilly terrain. A section point shall comprise of tension point with DB type or DC type or DD type towers as applicable.

(b) Extension

An individual span shall be as near to the normal design span as possible. In case an individual span becomes too short with normal supports on account of undulations in ground profile, one or both the supports of the span may be extended by inserting standard body and/or leg extension designed by the Contractor.

(c) Loading

There shall not be any upward force on suspension towers under normal working conditions and the suspension towers shall support at least the minimum weight span as provided in the designs. In case uplift is unavoidable, it shall be examined if the same can be overcome by adding standard body extensions to the towers failing which tension towers designed for the purpose shall be employed at such positions.

(d) Road Crossing

At all important road crossings, the tower shall be fitted with double suspension or tension insulator strings depending on the type of tower but the ground clearance at the roads under maximum conductor design temperature and in still air shall be such that even with conductor broken in adjacent span, ground clearance of the conductor from the road surfaces will not be less than 7.5m for 220KV lines. At all national highways suspension / tension towers shall be used and crossing span will not be more than 250 meters.

(e) River Crossings

In case of major river crossings towers shall be of suspension type and the anchor towers on either side of the main river crossing shall be DD type tower. Clearance required by navigation authority shall be provided. For non-navigable river, clearance shall be reckoned with respect to highest flood level (HFL).


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(f) Power Line Crossings

Where this line is to cross over another line of the same voltage or lower voltage, DA type tower with suitable extensions (if necessary) shall be used. Provisions to prevent the possibility of its coming into contact with other overhead lines shall be made in accordance with the directions of the Employer. All the works related to the above proposal shall be deemed to be included in the scope of the Contractor except if modifications are required to line below, in which case, the conditions to be agreed upon. The minimum clearance while crossing the 11 kV up to 132 kV lines shall be 4580 mm.

For power line crossings of voltage level of 132 kV and above, an angle towers

shall be provided on either side of DA type tower which can be temporary dead end condition with proper guying.

(g) Telecommunication Line Crossings

The angle of crossing shall be as near to 90 degree possible. However, deviation to the extent of 30 degree may be permitted under exceptionally difficult situations.

When the angle of crossing has to be below 60 degree, the matter will be referred to the authority in charge of the telecommunication System. On a request from the Contractor, the permission of the telecommunication authority may be obtained by the Employer.

Also, in the crossing span, power line support will be as near the telecommunication line as possible, to obtain increased vertical clearance between the wires.

(h) Details En-route

All topographical details, permanent features, such as trees, building etc. 17.5 m for 220 kV on either side of the alignment shall be detailed on the profile drawing.

1.8 Clearance from Ground, Building, Trees etc.

Clearance from ground, buildings, trees and telephone lines shall be provided in conformity with the Electricity Regulations of Nepal, 2050 as amended up to date.

1.8.1 The tree cutting shall be the responsibility of the Employer except for that required during survey. However, the Contractor shall count, mark and put proper numbers with suitable quality of paint at his own cost on all the trees that are to be cut by the Employer at the time of actual execution of the work as detailed below. Contractor may please note that Employer shall not pay any


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compensation for any loss or damage to the properties or for tree cutting due to Contractor’s work.

1.8.2 Any way leave which may be required by the Contractor shall be arranged by the Employer as required by work programme.

1.8.3 To evaluate and tabulate the trees and bushes coming within 20m on either side

of the central line alignment the trees will be numbered and marked with quality paint serially from angle point AP (I) onwards (where I is tree no.) and the corresponding number will be painted on the stem of trees at a height of 1 meter from ground level. The trees list should contain the following:

a) Girth (circumference) measured at a height of 1 meter from ground level.

b) Approximate height of the tree with an accuracy of +2 meters.

c) Name of the type of the species/tree.

d) The bushy and under growth encountered in the 40M belt should also be evaluated with its type, height, girth and area in square meters, clearly indicating the growth in the tree/bush statement.

Payment towards the above activities shall be borne by the Contractor.

1.8.4 Payment of compensation towards the clearance etc. will be the responsibility of the Employer.

1.9 Preliminary Tower Schedule

The profile sheets, duly spotted, along with preliminary schedules indicating type of towers, type of foundations, wind span, weight span, angle of deviation, river / road crossing and other details shall be submitted for the approval of the Employer. After approval the Contractor shall submit four more sets of the approved reports along with one soft copy on CD of final profile drawings to the Employer for record purpose.

1.10 Check Survey for Tower Location

1.10.1 The check survey shall be conducted to locate and peg mark the tower positions on ground conforming to the approved profile and tower schedule. In the process, it is necessary to have the pit centers marked according to the excavation marking charts. The levels, up or down of each pit center with respect to the center of the tower location shall be noted and recorded for determining the amount of earthwork required to meet the approved design parameters &/or for determining the suitable leg extensions.

1.10.2 On tower locations having undulations, levels shall be taken at every 2 meter along the diagonals (connecting diagonal legs) of tower in area of 20 X 20 meters


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profile of the ground along the diagonal shall be plotted and submitted to the Employer.

1.10.3 Changes in the preliminary tower schedule after detailed / check survey, if required, shall be carried out by the Contractor and he shall thereafter submit a final tower schedule for the approval of Employer. The tower schedule shall show position of all towers, type of towers, span length, type of foundation for each towers and the deviation at all angles as set out with other details.

1.10.4 Identification of ROW and land parcel 1.10.4.1 The Scope of work of "Check Survey” also includes the identification of the land

parcel and permanent structures owned by public as well as private individuals on the Right of Way of Transmission Line (ROW is 35m). The Contractor shall mark the tower locations showing its boundary covering all four foundation pads and submit the details of affected Land Parcel numbers along with their areas for all tower locations to the Employer after the approval of check survey. The detail of which should include land plot number, and owners name and address as obtained from the records of Land revenue Office (Maalpot) and Survey Division (Naapi Sakha) of the concerned districts. It will be the responsibility of the Contractor to hire the Land Surveyors (Amin) and other required manpower, survey instruments & accessories, cadastral maps and collect the required information as mentioned herein above.

1.10.4.2 The Contractor is also required to identify the land parcel, and its owners along

with the detail of area of the land required for the foundation footing and submit the report to the Employer for the Purpose of permanent acquisition of land. The area of land required for permanent acquisition shall be based on the designed area of the foundation footing.

1.10.4.3 The Employer shall initiate the process for acquiring the ROW of Transmission

Line as well as permanent land acquisition for plot of land area required for foundation footing after verification of the Contractors report. However, if any error is identified in the information submitted by the contractor needing re-identification of land plot and its owner’s names, the Contractor shall immediately mobilize the crews to rectify error and resubmit the report at no extra cost. No delay shall be acceptable for additional cadastral survey work in case the alignment is required to change during execution. Employer shall not be liable to make the additional payment in case the alignment is required to change due cause of delay execution of cadastral survey work.

1.10.4.4 The Employer, at the request of the Contractor shall request the various

Organizations or Offices of the Government of Nepal and local bodies to provide the necessary information to the Contractor. The Bidders are requested to


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familiarize themselves with the government rules & regulations and processes in the acquisition of land.

1.10.4.5 All cost incurred in this connection shall be included in Check Survey work.

However, the compensation cost of land and permanent structures along the ROW and land costs for permanent acquisition of land for tower pads shall be borne by the Employer. Also, the cost of publication of notice and various meeting expenses that are likely to be incurred during price/compensation fixation shall be borne by the Employer.

1.10.4.6 Loss of standing crops: The Employer shall make compensation for the loss of

standing crops due to project activities. However the Contractor shall assess the quantity of such losses and forward the Employer with the necessary field measurements to substantiate timely compensation to the owners.

1.10.5 Right of Way (ROW) Clearance (Forest) 1.10.5.1 The Scope of work in “Right of Way (ROW) Clearance” includes the marking of

trees that are likely to be felled down to clear the ROW, taking detailed log of trees and its measurement with the help of forest technician as deputed by the District Forest Office of the concerned District, and submit the report to the Employer.

1.10.5.2 The Employer shall forward the report to the Forest Office and shall initiate the

process of getting approval for felling of trees. Upon approval on the report from the District Forest Office, contractor shall initiate the process of marking (which is termed as “TANCHA”) of the trees in coordination with the concerned District Forest Office, the Employer shall immediately mobilize the work force and cut the marked trees, make logs/firewood in required sizes and transport and stack them in the stockyard as designated by the concerned District/Community Forest Office) under the close monitoring of forest technicians deputed by the District/Community Forest Office. Usually the wooden logs and fire wood is stacked in the size of 6.0m x1.52m.x1.52m, which is called as “chatta”.

1.10.5.3 The wooden logs shall be measured in net excluding the bark thickness and

firewood shall be measured in chatta and detail report shall be prepared by forest technician as deputed by the District Forest Office of the concerned District.

1.10.5.4 The per diem allowance of forest technician/guards etc as deputed by

District/Community Forest Office shall be paid by the Contractor as of actual man days involved in the works. It will be the full responsibility of the Contractor to manage proper security of wooden logs unless those are handed over to the concerned District/Community Forest Office.


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2.0 Environmental Conditions

2.1 Forest

The line route passing through forest stretches covered under this specification shall be furnished to the successful Bidder.

2.2 General Climatic Conditions

Climatic conditions shall be as indicated at Cl.5.0 of Section–1 of this Specification.

2.3 Statutory Regulations and Standards

2.3.1 Statutory Regulations

The Contractor is required to follow local statutory regulations stipulated in Electricity Regulations of Nepal, 2050 as amended and other local rules and regulations referred in this Specifications.

2.3.2 Reference Standard

2.3.2.1 The Codes and/or standards referred to in the specifications shall govern, in all cases wherever such references are made. In case of a conflict between such codes and/or standards and the specifications, latter shall govern. Such codes and/or standards, referred to shall mean the latest revisions, amendments/changes adopted and published by the relevant agencies unless otherwise specified.

2.3.2.2 Other internationally accepted standards which ensure equal or better performance than those specified shall also be accepted, subject to prior approval by the Employer.

3.0 Geotechnical Investigations

3.1 General

3.1.1 Employer desires that a detailed Geotechnical investigation be carried out at various tower locations to provide the designer with sufficiently accurate information, both general and specific, about the substrata profile and relevant soil and rock parameters at site on the basis of which the foundation of transmission line towers can be classified and selected/designed rationally. The entire soil investigation work at river crossing locations (if required) shall be carried out by the Contractor. The range of load intensities from the various structures is expected to be between 100 KN/sq. m and 500 KN/sq.m.

3.1.2 These specifications provide general guidelines for geotechnical investigation of normal locations, including marshy locations and those affected by salt water or saltpeter. Any other specific information required for design of foundation


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suitable for such locations shall be obtained by the Contractor and furnished to the Employer.

3.2 Scope

3.2.1 The scope of work includes detail soil investigations and furnishing bore log data at various tower locations. The provisional quantities have been indicated in Bill of Quantities considering detail soil investigation at selected tension tower locations. However, during actual execution of work, the quantities shall be decided by the Engineer - in - Charge, depending upon the soil strata and terrain. Based on the bore log data / soil parameter / soil investigation results, the Contractor shall recommend the type of foundations suitable for each locations and the same shall be got approved by the Employer. For other locations, trial pit of is to be done in every locations for foundation classification up to foundation depth and furnish bore log data including the depth of ground water table. No separate payment for trial pit shall be done. Based on the soil parameters, the Contractor has to recommend the type of foundation suitable for each locations and same shall be got approved by the Employer.

3.2.2 These specifications cover the technical requirements for a detailed Geotechnical investigation and preparation & submission of a detailed Geotechnical Report. The work shall include mobilization of all necessary tools and equipment, provision of necessary engineering supervision and technical personnel, skilled and unskilled labour, etc. as required for carrying out the entire field investigation as well as laboratory tests, analysis and interpretation of data collected and preparation of the Geotechnical Report. The Contractor shall also collect data regarding variation of subsoil water table along the proposed line route. The aforementioned work shall be supervised by a graduate in Civil Engineering having at least 5 years of site experience in geotechnical investigation work.

3.2.3 Contractor shall make its own arrangements to establish the co-ordinate system required to position boreholes, trial pits and other field test locations as per the drawings/sketches supplied by Employer. Contractor shall determine the reduced levels (R.L's) at these locations with respect to benchmarks used in the detailed survey. Two reference lines shall be established based on survey data/details. Contractor shall provide at site all required survey instruments to the satisfactions of the Employer so that the work can be carried out accurately according to specifications and drawings. Contractor shall arrange to collect the data regarding change of course of rivers, major natural streams and nalas, etc., encountered along the transmission line route from the best available sources and shall furnish complete hydrological details including maximum velocity, discharge, highest flood level (H.F.L) & scour depth etc. of the concerned rivers, major streams and nalas (canals).


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3.2.4 The field and laboratory data shall be recorded on the proforma recommended in relevant Indian Standards. Contractor shall submit to Employer two copies of field bore logs (one copy each to Employer’s site and corporate office) and the entire field records (countersigned by the Employer) soon after the completion of each borehole /test.

3.2.5 Whenever Contractor is unable to extract undisturbed samples, it shall immediately inform the Employer. Payment for boring charges shall be subject to Employer being satisfied that adequate effort has been made to extract undisturbed samples. Special care shall be taken for locations where marshy soils are encountered and Contractor in such cases shall ensure that specified numbers of vane shear tests are performed and the results correlated with other soil parameters.

3.2.6 One copy of all field records and laboratory test results shall be sent to Employer on a weekly basis. Employer may observe, the laboratory testing & procedures.

3.2.7 The Contractor shall interact with the Purchaser to get acquainted with the different types of structures envisaged and in assessing the load intensities on the foundation for the various types of towers in order to enable him to make specific recommendation for the depth, founding strata, type of foundation and the allowable bearing pressure etc.

3.2.8 After reviewing Contractor's geotechnical investigation draft report, Purchaser may call the contractor & his geotechnical engineer for discussions to be held at Employer’s site office / corporate office and give comments on the report. The report shall be redrafted & finalised by the contractor based on the comments and get the same approved from Employer’s site office. All expenditure associated with the redrafting and finalising the report including traveling etc. shall be deemed to have been included in the rates quoted for the geotechnical investigations.

3.2.9 Contractor shall carry out all work expressed and implied in Clause 3.2 of this specifications in accordance with requirements of the specification and satisfaction of the Employer.

3.3. General Requirements

3.3.1 Wherever possible, Contractor shall research and review existing local knowledge, records of test pits, boreholes, etc., types of foundations adopted and the behavior of existing structures, particularly those similar to the present project.

3.3.2 Contractor shall make use of information gathered from nearby quarries, unlined wells excavation etc. Study of the general topography of the surrounding areas will often help in the delineation of different soil types.


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3.3.3 Contractor shall gather data regarding the removal of overburden in the project area either by performing test excavations, or by observing soil erosion or land slides in order to estimate reconsolidation of the soil strata. Similarly, data regarding recent landfills shall be studied to determine the characteristics of such land fill as well as the original soil strata.

3.3.4 The water level in neighboring streams and watercourses shall be noted. Contractor shall make inquiries and shall verify whether there are abandoned underground works e.g. worked out ballast pits, quarries, old brick fields, mines, mineral workings etc. The possibility of damage to the structure, sewers, conduits and drainage system by subsidence shall also be investigated.

3.3.5 It is essential that equipment and instruments be properly calibrated at the commencement of the work. If the Purchaser so desires, Contractor shall arrange for having the instruments tested at an approved laboratory at their own cost and shall submit the test reports to the Employer. If the Employer desires to witness such tests, Contractor shall arrange for the same.

3.4 Codes and Standards for Geotechnical Investigations

All standards, specifications and codes of practice referred to herein shall be the latest editions including all applicable official amendments and revisions. In case of conflict between the present specifications and those referred to herein, the former shall prevail. Internationally accepted standards, which ensure equal or better performance than those specified shall also be accepted.

3.4.1 All work shall be carried out in accordance with the following Indian Standards and Codes:

Indian Title International and Standards (IS) Internationally Recognize Standard/Code

IS: 1080-1990 Codes of Practice for Design and Construction of Simple Spread Foundations

IS: 1498-1992 Classification and identification of ASTM D 2487/ Soils for General Engineering ASTM D 2488 purposes.

IS: 1888- 1982 Method of load tests on soil

IS: 1892-1992 Code of Practice for Subsurface Investigation for Foundation


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IS: 1904-1986 Code of Practice for Design and Construction of foundation in Soils: General Requirements.

IS: 2131-1992 Method of Standard Penetration ASTM D 1586 Soils

IS: 2132-1992 Code of Practice for Thin Walled ASTM D 1587 Sampling of Soils

IS: 2720-1992 Method of Test for Soils (Relevant ASTM D 420 Parts)

IS: 2809-1991 Glossary of Terms and symbols ASTM D 653 Relating to Soil Engineering

IS: 2810- 1979 Glossary of terms and symbols related to soil dynamics IS: 2911-1980 Code of Practice for Design and

construction of pile Foundations (Relevant Parts).

IS: 3025 Methods of Sampling and Testing (Physical and Chemical) for water used in industry.

IS: 3043-1991 Code of Practice for Earthing.

IS: 4078-1990 Code of Practice for Indexing and Storage of Drill Cores.

IS: 4091-1987 Code of Practice for Design and Construction of Foundations for Transmission Line Towers and Poles.

IS: 4434-1992 Code of Practice for in-situ Vane ASTM D 2573/ Shear Test for Soils. ASTM D 4648

IS: 4453-1992 Code of Practice for Exploration by Pits, Trenches, Drifts and Shafts.

IS: 4464-1990 Code of Practice for Presentation of Drilling Information and core description in Foundation Investigation


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IS: 4968- Method for Subsurface sound- (Part-II)-1992 ing for soils, dynamic method using cone and Bentonite slurry

IS: 5313-1989 Guide for Core Drilling observations.

IS: 6403-1990 Code Practice for Determination ASTM D 194 of Allowable Bearing Pressure on Shallow Foundation.

IS: 6926-1990 Code of Practice for Diamond Core Drilling for Site Investi- gation for River Valley Projects.

IS: 6935-1989 Method of Determination of Water level in a Bore Hole.

IS: 7422-1990 Symbols and Abbreviations for use in Geological Maps Sections and subsurface Exploratory Logs (Relevant parts).

IS: 8009 Code of Practice for Calculation (Part-I)-1993 of Settlements of Foundations (Shallow Foundations subjected to symmetrical Vertical Loads).

IS: 8764-1991 Method of Determination of Point Load Strength Index of Rocks.

IS: 9143-1991 Method of Determination of ASTM D 2938 Unconfined Compressive

Strength of Rock Materials.

IS: 9179-1991 Method of Preparation of Rock Specimen for Laboratory Testing. ASTM D 4543

IS: 9259-1992 Specification for Liquid Limit ASTM D 4318 Apparatus.

IS: 9640-1992 Specification for Split Spoon ASTM D 1586 Sampler.

IS: 10050-1992 Method of Determination of Slake ASTM D 4644 Durability Index of Rocks.


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IS: 11315- Description of Discontinuities in (Part-II)-1991 Rock Mass-Core Recovery and Rock Quality. CBIP Manual on transmission line towers, Chapter – 10 Foundations 3.5 Field Investigation for Soils

Tentative numbers of detailed soil investigation to be done is given in BPS.

3.5.1 Boring

Boreholes are required for detailed soil investigations.

3.5.1.1 General Requirements

a) Boreholes shall be made to obtain information about the subsoil profile, its nature and strength and to collect soil samples for strata identification and for conducting laboratory tests. The minimum diameter of the borehole shall be 150mm and boring shall be carried out in accordance with the provisions of IS: 1892 and this specification:

b) All boreholes shall be minimum 7m deep for normal open cast type foundations. If the strata with Standard Penetration Test–N value measured greater than 100 with characteristics of rock is met, the borehole shall be advanced by coring at least 3m further, limited to total 7m depth, with prior approval of the Purchaser.

c) Casing pipe shall be used when collapse of a borehole wall is probable. The bottom of the casing pipe shall at all times be above the test of sampling level but not more than 15cm above the borehole bottom. In case of cohesion less soils, the advancement of the casing pipe shall be such that it does not disturb the soil to be tested or sampled. The casing shall preferably be advanced by slowly rotating the casing pipe and not by driving.

d) In-situ tests shall be conducted and undisturbed samples shall be obtained in the boreholes at intervals specified hereafter. Representative disturbed samples shall be preserved for conducting various identification tests in the laboratory. Water table in the borehole shall be carefully recorded and reported following IS: 6935. No water or drilling mud shall be used while boring above ground water table. For cohesion less soil below water table, the water level in the borehole shall at all times be maintained slightly above the water table.

e) The borehole shall be cleaned using suitable tools to the depth of testing or sampling, ensuring least or minimum disturbance of the soil at the bottom


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of the borehole. The process of jetting through an open tube sampler shall not be permitted. In cohesive soils, the borehole may be cleaned by using a bailer with a flap valve. Gentle circulation of drilling fluid shall be done when rotary mud circulation boring is adopted.

f) On completion of the drilling, Contractor shall backfill all boreholes as directed by the Purchaser.

3.5.1.2 Auger Boring

Auger boring may be employed in soft to stiff cohesive soils above the water table. Augers shall be of helical or post hole type and the cuttings brought up by the auger shall be carefully examined in the field and the description of all strata shall be duly recorded in the field bore log as per IS: 1498. No water shall be introduced from the top while conducting auger boring.

3.5.1.3 Shell and Auger Boring

3.5.1.3.1 Shell and auger boring may be used in all types of soil that are free from boulders. For cohesion less soil below ground water table, the water level in the borehole shall always be maintained at or above ground water level.

3.5.1.3.2 The use of chisel bits shall be permitted in hard strata having SPT-N value greater than 100. Chisel bits may also be used to extend the borehole through local obstructions such as old construction, boulders, rocky formations, etc. The requirements in Clause 3.5.1.2 shall apply for this type of boring also.

3.5.1.4 Rotary Boring

Rotary boring method may be used in all types of soil below water table. In this method the boring is carried out by rotating the bit fixed at the lower end of the drill rod. Proper care shall be taken to maintain firm contact between the bit and the bottom of the borehole. Bentonite or drilling mud shall be used as drilling fluid to stabilize and protect the inside surface of the borehole. Use of percussion tools shall be permitted in hard clays and in dense sandy deposits.

3.5.2 Standard Penetration Test (SPT)

3.5.2.1 This test shall be conducted in all types of soil deposits encountered within a borehole, to find the variation in the soil stratification by correlating with the number of blows required for unit penetration of a standard penetrometer. Structure sensitive engineering properties of cohesive soils and sifts such as strength and compressibility shall not be inferred based on SPT values. No extra payment shall be made for carrying out Standard Penetration Tests.


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The test shall be conducted at depths as follows:

Location Depths (m)

Normal Soils 2.0, 3.0, 5.0, 7.0

3.5.2.2 The spacing between the levels of standard penetration testing and next undisturbed sampling shall not be less than 1.0m. The Equipments, other accessories, procedures for conducting the test and collection of the disturbed soil samples shall conform to IS: 2131 and IS: 9640. The rods shall be straight, tightly coupled and the air release valve shall be checked. The test shall be conducted immediately after reaching to the test depth and cleaning of bore hole.

3.5.2.3 The test shall be carried out by driving a standard split spoon sampler in the borehole by means of a 650N hammer falling freely from a height of 750mm for 450mm depth, recording the number of blows for every 75mm. The number of blow for the last 300mm drive shall be reported as measured N value.

3.5.2.4 This test shall be discontinued when blow count has reached 100 or the penetration is less than 25 mm for 50 blows, whichever is earlier, or sampler starts jumping. At the level where the test is discontinued, the number of blows and the corresponding penetration shall be reported. Sufficient quantity of disturbed soil samples shall be collected from the split spoon sampler for identification and laboratory testing. The sample shall be visually classified and recorded at the site as well as properly preserved without loss of moisture content and labeled.

3.5.3 Sampling

3.5.3.1 General

a) Sufficient number of soil samples shall be collected. Disturbed soil samples shall be collected for field identification and for conducting laboratory tests such as grain size (sieve) analysis, index properties, specific gravity, chemical analysis etc. Undisturbed samples shall be collected to estimate the physical, strength, swelling and consolidation properties of the soil.

b) All accessories and sampling methods shall conform to IS: 2132. All the representative disturbed and undisturbed samples collected in the field shall be classified at site as per IS: 1498. The specification for thin wall sampling tube and sampler heads should be as per IS: 11594.

c) All samples shall be identified with date, borehole or test pit number, date of sampling, etc. It is also essential to mark an arrow pointing towards the top surface of the undisturbed sample tube as the soil in-situ. Care shall be


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taken to keep the core and box samples vertically, with the arrow mark directing upwards. All undisturbed samples shall be properly trimmed at one end and suitably capped and sealed with molten paraffin wax on both sides. The Contractor shall be responsible for packing, storing in a cool place and transporting all the samples from site to the laboratory within seven days after sampling with proper protection against loss and damage.

3.5.3.2 Disturbed Samples

a) Disturbed soil samples shall be collected in boreholes at regular intervals. Jar samples weighing approximately (10 N)1 Kg shall be collected at 0.5m intervals starting from a depth of 0.5m below ground level and at every identifiable change of strata to supplement the boring records and at the levels of Standard Penetration Tests (SPT), obtained in a SPT sampler shall also be collected. Samples shall be stored immediately in airtight jars, which shall be filled to capacity as much as possible.

b) In designated borrow areas, bulk samples, from a depth of about 0.5m below ground level shall be collected to establish the required properties for use as a fill material. Disturbed samples weighing about 25kg (250 N) shall be collected at shallow depths and immediately stored in polythene bags as per IS: 1892. The bags shall be sealed properly to preserve the natural moisture content of the sample and shall be kept in wooden boxes for transportation.

3.5.3.3 Undisturbed Samples

The undisturbed soil samples shall be collected immediately after drilling and cleaning the borehole upto the desired depth. Effort shall be made that the preparations are made before hand to collect the sample after reaching to the desired depth. In each borehole undisturbed samples shall be collected at every change of strata and at depths as follows:

Location Depths (m) Normal foundations 1.0, 4.0, 6.0

3.5.3.3.1 The depth interval between the top levels of undisturbed sampling and standard penetration testing shall not be less than 1.0m. Undisturbed samples shall be of 100mm diameter and 450mm in length. Samples shall be collected in a manner to preserve the structure, density and moisture content of the soil. Accessories required for sampling and sampling procedures shall conform to IS: 1892 and IS: 2132 and other related IS Codes. Undisturbed sampling in sand shall be done using compressed air technique mentioned in IS: 8763.

a) Undisturbed sampling in cohesive soil:

Undisturbed samples in soft to stiff cohesive soils shall be obtained using a thin walled sampler. In order to reduce the wall friction, suitable precautions, such as


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oiling the surfaces shall be taken. The sampling tube shall have a smooth finish on both surfaces and a minimum effective length of 450mm. The area ratio of sampling tubes shall be less than 12.5%. However, in case of very stiff soils area ratio up to 20% shall be permitted. Inside clearance ratio and outside clearance ratio shall be as specified by IS code.

b) Undisturbed samples in very loose saturated sandy and silty soils and very soft clays shall be obtained by using a piston sampler consisting of a sampling cylinder and piston system. In soft clays and silty clays, with water standing in the casing pipe, piston sampler shall be used to collect undisturbed samplers in the presence of expert supervision.

Accurate measurements of the sampling depth, height of sampler, stroke and length of sample recovered shall be recorded. After the sampler is pushed to the required depth, the cylinder and piston system shall be drawn up together, ensuring that there shall not any disturbance to the sample.

c) Undisturbed sampling in cohesion less soil

Undisturbed samples in cohesion less soils shall be obtained as per the procedure given in IS: 8763. Compressed air Sampler shall be used to take sample of cohesion less soils below water table.

d) The sampler should be cleaned (not rusted), oiled and connected with straight drill rods coupled tightly. The air-released valve should be checked every time before lowering the sampler. At the time of lowering the sampler it should be ensured that bore hole is cleaned, casing is not below the depth of sampling and water level in the bore hole is above the water table preferably up to ground surface if sampling is done below water table.

e) The collected sample should be sealed on both ends of the sampler with wax. They should be given identification numbers and kept in the airtight wooden boxes. They should be transported in truck with a care that the structure of soil samples would not change due to vibration during transportation. They should be kept in a testing laboratory and should be tested within seven days or before.

3.5.4 Ground Water Table

3.5.4.1 One of the following methods shall be adopted for determining the elevation of ground water table in boreholes as per IS: 6935 and the instructions of the Purchaser:

a) In permeable soils, the water level in the borehole shall be allowed to stabilise after depressing it adequately by bailing before recording its level. Stability of sides and bottom of the boreholes shall be ensured at all times.

b) For both permeable and impermeable soils, the following method shall be suitable. The borehole shall be filled with water and then bailed out to


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various depths. Observations on the rise or fall of water level shall be made at each depth. The level at which neither fall nor rise is observed shall be considered the water table elevation and confirmed by three successive readings of water level taken at two hours interval.

3.5.4.2 If any variation of the ground water level is observed in any specific boreholes, the water level in these boreholes shall be recorded daily during the course of the filed investigation. Levels in nearby wells, streams, etc., if any, shall also be noted in parallel. Care should be taken to ensure any abrupt change in water level in borehole is recorded.

3.5.4.3 Subsoil water samples

a) Subsoil water samples shall be collected for performing chemical analysis. Representative ground water samples shall be collected when first encountered in boreholes and before the addition of water to aid boring or drilling.

b) Chemical analysis of water samples shall include determination of pH value, turbidity, sulphate, carbonate, nitrate and chloride contents, presence of organic matter and suspended solids. Chemical preservatives may be added to the sample for cases as specified in the test methods or in applicable Indian Standards. This shall only be done if analysis cannot be conducted within an hour of collection and shall have the prior written permission and approval of the Purchaser.

3.5.5 Dynamic Cone Penetration Test (For marshy locations, with bentonite slurry)

Dynamic cone penetration test shall be conducted with bentonite slurry to predict stratification, density, bearing capacity of granular soils, etc. The test shall be conducted by driving a standard size cone attached to the bottom of a string of straight and tightly coupled drill rods to the specified depth or refusal, whichever comes first. Refusal shall be considered when the blow count exceeds 100 for 300mm penetration. The Equipment, accessories required for performing the test, test procedures, field observations and reporting of results shall conform to IS: 4968, Part-II. The driving system shall comprise of a 650 N weight having a free fall of 750mm. The cone shall be 600 and of 65mm diameter provided with vents for continuous flow of bentonite slurry through the cone and rods in order to avoid friction between the rods and soil. On completion of the test the results shall be presented as a continuous record of the number of blows required for every 300mm penetration of the cone into the soil in a suitable chart supplemented by a graphical plot of blow count for 300mm penetration vs. depth. On completion of the test, the results shall be presented on the format approved by the Purchaser.


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3.5.6 Dynamic cone penetration test without slurry

The test shall be conducted for prediction of different soil strata, their relative strength or density or both. The 50mm diameter 600 cone shall be fitted loosely to the driving rod through a cone adopter. The cone shall be driven in to the soil by allowing the 650 N weight hammers to fall freely through a height of 750mm each time. The number of blows for every 75mm penetration shall be recorded. The process shall be repeated till the cone is driven to the required depth. The penetration depth shall be limited to 5m in cohesion less soil and 10m in mixed soil with some binding material. The cone driving rods, driving head, hoisting equipment shall conform to IS: 10589. The test and report should be prepared as per guidelines of IS: 4968 (Part I).

3.5.7 Vane Shear Test (required for boreholes where UDS is not possible in marshy locations)

Field vane shear test shall be performed inside the borehole to determine the shear strength of cohesive soils, especially of soft and sensitive clays, which are highly susceptible to sampling disturbance. This test shall be conducted by advancing a four-winged vane of suitable size (75mm or 100mm diameter as per the soil condition) into the soil at the desired depth and measuring the torque required to rotate the vane. The equipments and accessories required for conducting test, test procedures and field observations shall correspond to IS: 4432. Tests may also be conducted by direct penetration from ground surface. If the cuttings at the test depth in the borehole show any presence of gravel, sand, shells, decomposed wood, etc., which is likely to influence the test results substantially, the test at that particular depth may be omitted with the permission of the Purchaser. However, the test shall be conducted at a depth where these obstructions cease to occur. On completion of the test, the results shall be reported in an approved Performa as specified in IS: 4434, Appendix-A.

3.6 Field Investigation for Rock

3.6.1 Rock Drilling

3.6.1.1 If, during the investigations, large hard fragments or natural rock beds like but not limited to igneous, sedimentary and metamorphic formations are encountered, work shall proceed with core drilling methods. The equipment and procedures for this operation shall conform to IS: 1892. The starting depth of drilling in rock shall be certified by the Purchaser. At the end of the investigation, the hole drilled in rock shall be backfilled with grout consisting of 1 part cement and 3 parts sand by weight.

3.6.1.2 Drilling shall be carried out with NX size tungsten carbide (TC) or diamond tipped drill bits, depending on the type of rock and according to IS: 6929. Suitable type


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of drill bit (TC/Diamond) and core catchers shall be used to ensure continuous and good core recovery. Core barrels and core catchers shall be used for breaking off the core and retaining it when the rods are withdrawn. Double and triple tube core barrels shall be used to ensure better core recovery and to retrieve cores from layers of bedrock. Water shall be circulated continuously in the hollow rods and the sludge conveying the rock cuttings to the surface shall be collected. A very high core recovery ratio shall be aimed in order to obtain a satisfactory undisturbed sample. Attempt shall be made to recover cores of 1.5m in length. Normally TC bit shall be used. Change over to a diamond bit shall require the specific written approval of the Purchaser, and his decision as to whether a TC or a diamond bit is to be used shall be final and binding on Contractor.

3.6.1.3 No drilling run shall exceed 1.5m in length. If the core recovery is less than 80% in any run, the length of the subsequent run shall be reduced to 0.75m. During drilling operations observations on return water, loss of water, rate of penetration etc. shall be made and reported as per IS: 5313.

a) The colour of return water at regular intervals, the depth at which any change of colour of return water is observed, the depth of occurrence and amount of flow of hot water, if encountered, shall be recorded.

b) The depth through which a uniform rate of penetration was maintained, the depth at which marked change in rate of penetration or sudden fail on drill rod occurs, the depth at which any blockage of drill bit causing core loss, if any, shall be recorded.

c) Any heavy vibration or torque noticed during the drilling should be recorded together with the depth of occurrence.

c) Special conditions like the depth at which grouting was done during drilling, presence of artesian conditions, loss of drilling fluid,

d) observations of gas discharge with return water, etc., shall also be observed and recorded.

e) All the observations and other details shall be recorded as per daily drill and reported in a proforma as given in IS: 5313, Appendix A.

3.6.2 Core Sampling

3.6.2.1 Core samples shall be extracted by the application of a continuous pressure at one end of the core with the barrel held horizontally without vibration. Friable cores shall be extracted from the barrel directly into a suitably sized half round plastic channel section. Care shall be taken to maintain the direction of extrusion of sample same as while coring, to avoid stress reversal.


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3.6.2.2 Immediately after withdrawal from the core barrel; the cores shall be placed in a tray and transferred to core boxes specially prepared for this purpose. The boxes shall be made from seasoned timber or any other durable material and shall be indexed on top of the lid according to IS: 4078. The cores shall be numbered serially and arranged in the boxes in a sequential order. The description of the core samples shall be recorded as instructed in IS: 4464. Where no core is recovered, it shall be recorded as specified in the standard. Continuous records of core recovery and rock quality designation (RQD) are to be mentioned in the bore log in accordance with IS: 11315 (Part-II). Color photograph of cores shall be taken. The core shall be put in sealed polythene bags. The core boxes should be transported carefully so that core should not be broken. They should be stored in dry place and should be sent for testing immediately.

3.7 Laboratory Testing

3.7.1 Essential Requirements

a) Depending on the types of substrata encountered, appropriate laboratory tests shall be conducted on soil and rock samples collected in the field. Laboratory tests shall be scheduled and performed by qualified and experienced personnel who are thoroughly conversant with the work. Tests indicated in the schedule of items shall be performed on soil, water and rock samples as per relevant IS codes. One copy of all laboratory test data records shall be submitted to Purchaser progressively every week. Laboratory tests shall be carried out concurrently with the field investigations, as initial laboratory test results could be useful in planning the later stages of fieldwork. A schedule of laboratory tests shall be established by Contractor to the satisfaction of the Purchaser within one week of completion of first borehole.

b) Laboratory tests shall be conducted using approved apparatus complying

with the requirements and specification of Indian Standards or other approved standards for this type of work. It shall be checked that the apparatus are in good working condition before starting the laboratory tests. Calibration of all the instruments and their accessories shall be done carefully and precisely at an approved laboratory.

c) All samples, whether undisturbed or disturbed shall be extracted, prepared and examined by competent personnel properly trained and experienced in soil sampling, examination, testing and in using the apparatus in conformance with the specified standards.

d) Undisturbed soil samples retained in liners or seamless tube samplers shall

be removed, without causing any disturbance to the samples, using suitably designed extruders just prior to actual testing. If the extruder is horizontal,


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proper support shall be provided to prevent the sample from breaking. For screw tube extruders, the pushing head shall be free from the screw shaft so that no torque is applied to the soil sample in contact with the pushing head. For soft clay samples, the sample tube shall be cut by means of a high-speed hacksaw to proper test length and placed over the mould before pushing the sample into it with a suitable piston.

e) While extracting a sample from a liner or tube, care shall be taken to ensure

that its direction of movement is the same as that during sampling to avoid stress reversal.

f) The preparation of soil samples should be conforming to guide lines of IS: 2720 (Part – I).

3.7.2 Tests

Tests as indicated in this specification and as may be requested by the Purchaser, shall be conducted. These tests shall include but may not be limited to the following:

a) Tests of undisturbed and disturbed samples

- Visual and engineering classification;

- Sieve analysis and hydrometric analysis;

- Liquid, plastic and shrinkage limits;

- Specific gravity;

- Chemical analysis

- Swell pressure and free swell index determination

- Proctor compaction test.

b) Tests of undisturbed samples:

- Bulk density and moisture content;

- Relative density (for sand),

- Unconfined compression test;

- Box shear test (for sand);

- Triaxial shear tests (depending on the type of soil and field conditions on undisturbed or remoulded samples):

i) Unconsolidated undrained;


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ii) Consolidated drained test;

- Consolidation.

c) Tests on rock samples

- Visual classification;

- Moisture content, porosity and density;

- Specific gravity;

- Hardness

- Stake durability;

- Unconfined compression test (both saturated and at in-situ water content;

- Point load strength index;

- Deformability test (both saturated and dry samples).

d) Chemical analysis of sub soil water.

3.7.3 Salient Test Requirement

a) Triaxial shear tests shall be conducted on undisturbed or remolded soil samples, saturated by the application of back pressure. Only if the water table is at sufficient depth so that chances of its rising to the base of the footing are small or nil, the triaxial tests shall be performed on specimens at natural moisture content. Each test shall be carried out on a set of three test specimens from one sample at cell pressures equal to 100, 200 and 300 KN/sq.m respectively or as required depending on the soil conditions. Great care shall be taken to select the rate of shearing depending upon the soil type and drainage condition. The filter paper and the porous stone shall be cleaned and de-aired properly by boiling in water (for a minimum of 10 minutes after reaching the boiling temperature) before commencement of each test.

b) Direct shear test shall be conducted on undisturbed or remolded soil samples. The three normal vertical stresses for each test shall be preferably 100, 200 and 300 KN/sq.m. and or simulating with stresses in field conditions. Cohesive soil shall be compacted to the required density and moisture content in mould and remolded sample shall be extracted and trimmed to require size. Cohesion less soil shall be tamped in the shear box itself. The plane grid plate, perforated shall be used in shear box as per requirement of drainage condition of test. The serration of grid plate shall be right angle to the direction of shear. The filter paper and the porous stone shall be cleaned and de-aired properly by boiling in water (for a


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minimum of 10 minutes after reaching the boiling temperature) before commencement of each test. The rate of shearing shall be simulating with drainage condition based upon design requirement and soil type. The density and water content of soil shall be measured in each test.

c) Consolidation test shall have loading stages of 10, 25, 50, 75, 100, 200, 400 and 800 KN/sq.m. and simulating with stresses in field condition. For each loading stage, the settlement shall be recorded at convenient time interval till settlement is very negligible or completely over. Usually a period of 24 hours will be sufficient. While putting soil specimen in consolidation ring the unnatural voids shall not be left against the inner face of the ring. The top and bottom shall project above and below the edges of the ring to enable final trimming. The density and water content of soil sample shall be measured. Rebound curve shaft be recorded for all samples by unloading the specimen at its in-situ stress. Additional rebound curves shall also be recorded wherever desired by the Purchaser;

d) Chemical analysis of subsoil shall include determination of PH value, carbonate, sulphate (both SO3 and SO4), chloride and nitrate contents, organic matter, salinity and any other chemicals, which may be harmful to the foundation material. The contents in the soil shall be indicated as percentage (%);

e) Chemical analysis of subsoil water samples shall include the determination of properties such as colour, odour, turbidity, PH value and specific conductivity both at 250C, and chemical contents such as chlorides, nitrates, carbonates, sulphates (both SO3 and SO4), organic matter and any other chemical harmful to the foundation material. The contents shall be indicated as parts per million (PPM) by weight.

3.8 Geotechnical Investigation Report

3.8.1 General

a) On completion of all the field and laboratory work, the Contractor shall submit a formal report containing geological information of the region, procedures adopted for geotechnical investigation, field observations and test results, laboratory observations and test results, summarized test data, conclusions and recommendations. The report shall also include detailed bore logs, subsoil sections, field test results, laboratory observations and test results both in tabular as well graphical form, practical and theoretical considerations for the interpretation of test results, supporting calculations for the conclusions drawn, etc.


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b) Initially, Contractor shall submit three copies of the draft report for Purchaser's review. After receiving Purchaser's comments, if any, Contractor shall incorporate the same in the report and resubmit the revised report for approval. Ten copies of the detailed final approval report shall be submitted to Purchaser together with one set of reproducible of the graphs, tables etc.

c) The detailed final report based on field observations, in-situ and laboratory tests shall encompass theoretical as well as practical considerations for foundations for different types of structures as discussed in Clause 2.3 of Section-IV of this specification.

3.8.2 Data to be furnished

3.8.2.1 The report shall also include but not limited to the following:

a) A plot plan/location plan showing the locations and reduced levels of all field test e.g. boreholes, trial pits, static cone penetration tests, dynamic cone penetration tests, etc., properly drawn to scale and dimensioned with reference to the established grid lines;

b) A true cross section of all individual boreholes and test pits with reduced levels and co-ordinates showing the classification and thickness of individual stratum, position of ground water table, various in-situ tests conducted, samples collected at different depths and the rock stratum, if encountered;

c) Geological information of the area including geomorphic, geological structure, litho logy, stratigraphy and tectonics, core recovery and rock quality designation (RQD), quantitative description of discontinuities in rock mass along the line route etc.;

d) Observations and data regarding change of course of rivers, velocity, flood details (including past history) etc. in the vicinity of the locations

e) Past observations and historical data, if available, for the area or for other areas with similar soil profile, or with similar structures in the surrounding areas;

f) Plot of Standard Penetration Test (uncorrected and corrected N values) with depth for each test site;

g) Results of all laboratory test summarized according to Table 4.0 (i) for each sample as well as (ii) for each layer, along with all the relevant charts, tables, graphs, figures, supporting calculations, conclusions and photographs of representative rock cores.


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h) For all triaxial shear tests, stress vs. strain diagrams as well as Mohr's circle envelopes shall be furnished. If backpressure is applied for saturation, the magnitude of the same shall be indicated. The value of modulus of elasticity (E) shall be furnished for all tests along with relevant calculations.

If it is not possible to get proper c- values of Mohr circles, the same may be obtained from p-q plots.

i) For all consolidation tests, the following curves shall be furnished

i) e vs. log p;

ii) e vs. p;

iii) Compression vs log t or Compression vs t (depending upon the shape of the plot, for proper determination of coefficient of consolidation). The point showing the initial condition (e0, p0) of the soil shall be marked on the curves;

j) The procedure adopted for calculating the compression index from the field curve and settlement of soil strata shall be clearly specified. The time required for 50% and 90% primary consolidation along with secondary settlements, if significant, shall also be calculated.

k) In static cone penetration test, plot of penetration resistance and friction jacket resistance with depth along with log of borehole shall be shown.

l) In field Vane shear test the calculations, results and interpretation shall be submitted

m) A set of longitudinal and transverse soil/rock profiles connecting various boreholes in order to give a clear picture of the variation of the sub soil strata as per IS: 6065.

n) For Rock, drilling procedure adopted, drilling parameters, core recovery, RQD, core logs, joint parameters, core boxes with proper numbering, core box photographs and water levels etc. should be furnished in the report.

Table 4.0

SUMMARY OF RESULTS OF LABORATORY TESTS ON SOIL AND WATER SAMPLES

1. Bore hole/ test pit. no

2. Depth (m)

3. Type of sample


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4. Density (kg/m3)

a) Bulk

b) Dry.

c) Submerged

5. Water content (%)

6. Particle Size (%)

a) Gravel

b) Sand

c) Silt

d) Clay

7. Consistency properties

a) LL

b) PL

c) Pl

d) L1

8. Soil

a) Classification-IS

b) Description

c) Specific gravity

9. Strength Test

a) Type

b) c (Cohesion)

c) (angle of internal fraction)

10. Consolidation Test

a) e0

b) Pc

c) Cc

d) DP


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e) Mv

f) Cv

11. Shrinkage limit (%)

12. Swell Test

a) S.Pr

b) FS

13. Relative Density (%)

14. Remarks

Notations:

I. For type of Sample:

DB - Disturbed bulk soil sample.

DP - Disturbed samples from cutting edge of undisturbed soil sample.

Rm - Remoulded soil sample

UB - Undisturbed block soil sample

US - Undisturbed soil sample by sampler

W - Water sample

II. For Strength Test:

SCPT - Static Cone Penetration Test

UCC - Unconfined Compression Test

VST - Vane Shear Test

Tuu - Unconsolidated Undrained Traixial Test

Note: Replace T by D for Direct Shear Test

Tod - Consolidation Drained Triaxial Test

III. For Others:

LL - Liquid Limit (%)

PL - Plastic Limit

Pl - Plasticity Index

LI - Liquidity Index


SECTION- III

VOLUME-II

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C - Cohesion (kPa)

O - Angle of Internal Fraction (degrees)

S - Pr. - Swelling Pressure (kPa)

e0 - Initial Void Ratio

Pc - Reconsolidation Pressure (kPa)

Cc - Compression Index

DP - Change in pressure (kPa)

mv - Coefficient of Volume Compressibility (m2/KN)

Cv - Coefficient of Consolidation (m2/hr)

IV. For Chemical Test

As per Specifications - Clause 3.8.4

Rock samples

1. Drill hole no., location

2. Depth

3. Method of drilling

4. Mineral composition

5. Density

6. Moisture content

7. Specific gravity

8. Hardness

9. Sonic wave velocity

10. Slake durability index

11. Unconfined compressive strength, c

- Saturated

- Insitu water content

12. Modulus of Elasticity, Et

13. Poisson’s ratio,

14. Brazilian tensile strength, tp


SECTION- III

VOLUME-II

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15. Point load strength, tp

16. Shear strength parameter, c, (Triaxial compression)

17. Rock joint parameters

18. Percentage core recovery

19. RQD (Rock Quality Designation)

3.8.3 Recommendations

3.8.3.1 Recommendations shall be provided for each tower location duly considering soil type and tower spotting data. The recommendations shall provide all design parameters and considerations required for proper selection, dimensioning and future performance of tower foundations, as discussed in this part but not limited to Clause 2.3 of Section IV of this specification and the following

a) The subsurface material must provide safe bearing capacity and uplift resistance by incorporating appropriate safety factors specified in Clause 2.3 of Section IV of this specification all the while experiencing small deformations throughout, thereby avoiding rupture under ultimate loads;

b) Movement of the foundation, including short and long term components under transient and permanent loading, shall be strictly controlled with regard to settlement, uplift, lateral translation and rotation:

c) Co-efficient of permeability of various sub soil and rock strata based on in-situ permeability tests.

Cone resistance, fractional total resistance, relation between core resistance, Standard Penetration Test No value, and settlement analysis for different sizes of foundation based on static cone penetration test.

d) For locations where use of shallow foundation may be required the following shall be indicated with comprehensive supporting calculations:

i) Net Safe allowable bearing pressure for isolated square footing of sizes 2.0, 3.0, and 4.0 m at three different founding depths of 1,2 and 3m below ground level considering both shear failure and settlement criteria giving reasons for type of shear failure adopted in the calculation.

ii) Net safe allowable bearing pressure for raft foundations of widths greater than 5m at 2.0, 3.0 and 4.0m below ground level considering both shear failure and settlement criteria.

iii) Rate and magnitude of settlement expected of the structure.


SECTION- III

VOLUME-II

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iv) Net safe bearing capacity for foundation sizes mentioned in Para (i) above, modulus of sub grade reaction, modules of elasticity from plate load test results along with time settlement curves in both natural and log graph, variation of Modulus of sub grade reaction with size, shape and depth of of foundation.

e) The stable slopes for shallow and deep excavations, active and passive earth pressure at rest and angle of repose for sandy soils shall be furnished. the loading of the foundations shall not compromise the stability of the surrounding subsurface materials and the stability of the foundation shall be ensured against sliding or overturning:-

f) Depending on the subsurface material, water table level and tower type, either reinforced concrete isolated pad and chimney or any other type of foundations shall be installed at a given location

g) Net Safe allowable bearing pressure and uplift resistance shall be provided for the various sizes of isolated square footings founded at various depths below ground level considering both shear failure and movement criteria; rate and magnitude of movement expected of the structure (settlement, uplift, rotation) shall also be given.

h) In cases where normal open cast appear to be impractical, special pile foundations shall be given due consideration along with the following:

i) Type of pile foundation and reasons for recommending the same duly considering the soil characteristics.

ii) Suitable founding strata for the pile:

iii) Estimated length of pile for 500, 750 and 1000 KN and 4500 KN capacities; end bearing and frictional resistance shall be indicated separately:

iv) Magnitude of negative skin fraction or uplift forces due to soil swelling.

i) Where the subsoil water and soil properties are found to be chemically aggressive. Contractor shall take suitable precautions during construction including any protective coating to be applied on the foundations; susceptibility of soil to termite action and remedial measures for the same shall be dealt with;

j) Suitability of locally available soils at site for filling, backfilling and adequate compaction shall be investigated.


SECTION- III

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k) If expansive soil such as block cotton soil is encountered recommendation of removal or retainment of the same shall be given in the latter case, detailed specifications of special requirements shall also be given;

i) Susceptibility of subsoil strata to liquefaction in the even of earthquake and remedial measures, if required, shall be considered.

m) Any other information of special significance such as dewatering schemes, etc., which may have a bearing on the design and construction, shall be provided.

n) Recommendations for additional soil investigations, beyond the scope of the present work, shall be given if Contractor considers such investigations necessary.

3.8.4 Hydro-geological Conditions

3.8.4.1 The maximum elevation of ground water table, amplitudes of its fluctuations and data on water aggressively with regard to foundation structure materials shall be reported. While preparing ground water characteristics the following parameters should be specified for each aquifer:

a) bicarbonate alkalinity mg-eq/(deg),

b) pH value

c) content of aggressive carbon dioxide, mg/l;

d) content of magnesia salts. mg/l, recalculated in terms of ions Mg2+

e) content of ammonia salts, mg/l, recalculated in terms of ions NH4+

f) content of caustic alkalis, mg/l, recalculated in terms of ions Na+ and K+

g) contents of chlorides,mg/l, recalculated in terms of ions Cl-

h) contents of sulphates, mg/l, recalculated in terms of ions SO4

I) aggregate content of chlorides, sulphates, nitrates, carbonates and other salts,mg/l.

3.9 Rates and Measurements

3.9.1 Rate

The contractor's quoted rates shall be inclusive of making observations, establishing and furnishing the ground level and co-ordinates at the location of each bore hole, test pit etc. No extra payments shall be made for conducting Standard Penetration Test, collecting, packing, transporting of all samples and cores, preserving, recording and submission of results on approved formats.


Section IV: Tower, Foundation, Erection, Stringing, and Commissioning of Line Volume – II: Technical Specifications

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SECTION- IV

TOWER, FOUNDATION, ERECTION, STRINGING AND COMMISSIONING OF LINE

1.0 Transmission Tower

1.1 General Description of the Tower

1.1.1 The towers shall be self-supporting, hot dip galvanised, latticed steel type & designed to carry the line conductors with necessary insulators, earth wire/ OPGW and all fittings under all loading conditions. Outline diagram of double circuit towers are enclosed with the Specification.

1.1.2 The tower shall be fully galvanised using mild steel or/and high tensile steel sections as specified in clause no. 1.6. Bolts and nuts with spring washer are to be used for connections.

1.1.3 The towers shall be of the following types:

A) Double Circuit towers (DA, DB, DC & DD/DDE)

B) Special towers.

1.2 Classification of Towers

1.2.1 The towers for 220 kV Lines are classified as given below:

_______________________________________________________________ Type of Deviation Typical Use

Tower Limit

_______________________________________________________________

DA 0 to 2 degrees To be used as tangent / suspension Tower

with suspension insulator string

DB 0 to 15 degrees a) Angle towers with tension insulator string.

b) Also to be used for uplift force resulting from an uplift span up to 200m under broken wire conditions c) Also to be used for Anti Cascading Condition.

DB 0 degree To be used as Section Tower. DC 15 to 30 degrees a) Angle tower with tension insulator string.



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b) Also to be used for uplift forces resulting from an uplift span up to 360m under broken wire condition.

c) Also to be used for anti cascading condition.

DC 0 deg. To be used as Section tower. DD 30 - 60 deg. a) Angle tower with tension insulator string. b) Also to be used for uplift forces resulting from an uplift span up to 300m under

broken wire condition. c) Dead end with 0 deg to 15 deg deviation

both on line side and substation side (slack span)

DDE 0 deg. a) Complete dead end.

b) For river crossing anchoring with longer wind span & 0 deg. deviation on crossing span side and 0 deg to 30 deg. deviation on other side.

_______________________________________________________________

Notes

i) All above towers shall be designed for single circuit strung condition also considering that all conductors and earthwire of one circuit would be placed on one side of tower.

ii) All above towers can also be used for longer span with smaller angle of deviations without infringement of ground clearance.

iii) The above table provides indicative classification of Towers. Tower spotting data for various towers to be used in the transmission lines shall be given by the contractor during execution stage.

1.2.2 Towers for Major Crossings

The above towers shall also be used with suitable modifications for very long spans (spans more than that of given in clause no. 1.3) which can not be crossed by normal tower with extensions as given in clause.no.1.2.3 like valley and river crossings etc. These Towers shall be developed by strengthening the above DA, DB, DC and DD type towers as per the site requirement. Additional weight of tower due to strengthening shall be paid on pro-rata basis derived from the quoted price and final weight of the standard (+/- 0) tower after successful testing.



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1.2.3 Extensions

1.2.3.1 The Double Circuit towers shall be designed so as to be suitable for adding -4.5M, –3M, -1.5M, 1.5M, 3M, 4.5M, 6M, 7.5M and 9M body extensions / leg extensions for maintaining adequate ground clearances without reducing the factor of safety (actual stress /allowable stress) available for the members of tested extensions in any manner. Reference drawing for leg extension arrangement is enclosed in the Bid Document.

1.2.3.2 The provision for addition of 18/25M body extension to tower types DA and DD is also kept. For Power Line Crossing or any other obstacle, tower types DA or DD can be used with 18/25 M extensions depending, upon the merit of the prevailing site condition. The maximum reduced spans for DA and DD type towers shall be mentioned in the tower spotting data. However this shall, in no case be less than 250 meters. Payment for the additional weight due to 18/25M extension shall be made as described in clause no. 1.2.2.

1.2.3.3 The towers shall be designed for providing unequal leg extensions with maximum difference between the shortest and the longest leg of 3M for DA tower and 6M for DB, DC & DD towers. These unequal leg extensions to be provided in the design shall be used during tower spotting / execution stage to optimise the benching / revetment requirement.

1.2.3.4 In situations where difference in leg differential does not suit the standard unequal leg extension provisions on the towers mentioned above, suitable chimney extensions shall be provided to reduce benching/revetment requirement. Additional volumes of foundation due to chimney extensions shall be paid on pro-rata basis derived from the quoted price and final volumes of the standard foundation of same classification for that tower.

1.2.3.5 The leg extensions, unequal leg extensions, chimney extensions and / or a combination of these suitable for a tower location shall be selected on the basis of techno-economics evaluation.

1.2.3.6 All above body / leg extension provisions to towers shall be treated as part of normal tower only.

1.3 Spans

1.3.1 Design Span or Normal Span

The Design Span or Normal Ruling Span of the line is 350m for 220KV transmission line.

1.3.2 Wind Span

The wind span is the sum of the two half spans adjacent to the tower under consideration. For normal horizontal spans this equals to normal ruling span.



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1.3.3 Weight span

The weight span is the horizontal distance between the lowest point of the conductors on the two spans adjacent to the tower. For spotting of structures, the span limits are given in Table 1.1 below

TABLE 1.1

TOWER TYPE NORMAL CONDITION BROKEN WIRE CONDITION

MAX. (m) MIN. (m) MAX. (m) MIN. (m)

DA 525 200 315 100

DB, DC 525 0 315 -200

DD 525 0 315 -300

1.3.4 In case at certain locations where actual spotting spans exceed the design

spans and cross-arms and certain members of towers are required to be modified/ reinforced, in that case design, structural & shop drawings for the modified/ reinforced towers will be prepared by the Contractor as per requirement on basis of approved line diagram without any additional financial implications to the Employer for the design and drawings.

1.4 Electrical Clearances

1.4.1 Ground Clearance

The minimum ground clearance from the bottom conductor shall not be less than 7015 mm for 220KV lines at the maximum sag conditions i.e at 80°C and still air.

a) An allowance of 150mm shall be provided to account for errors in stringing.

b) Conductor creep shall be compensated by over tensioning the conductor at a suitable temperature, lower than the stringing temperature.

1.4.3 Power Line Crossing

Minimum clearance between power lines to power line crossing should be 4580 mm.

1.4.4 Live Metal Clearance

The minimum live metal clearance to be provided between the live parts and steel work of superstructure shall be as given in Table 1.2



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TABLE 1.2

DESCRIPTION SWING ANGLE LIVE METAL CLEARENCE -------------------- --------------------- ----------------------------------- 1000 M EL ----------------------------------- Suspension String NIL 2130 mm (Single / Double) 15 Degree 1980 mm 30 Degree 1830 mm 45 Degree 1675 mm Tension String -- 2130 mm (Single / Double) Jumper NIL 2130 mm 10 Degree 2130 mm 20 Degree 1675 mm

NOTE: in case of pilot insulator strings, the angle of swing of the jumper along with the pilot string shall be considered as 15 deg.

1.4.5 Bidder shall adopt same cross arm design where jumper is projecting outside of cross-arm for DD/DDE type tower, used as dead end and angle tower.

1.4.6 For computing the live metal clearances, the dimensions of Single Suspension, Double Suspension, Single Suspension Pilot, Single Tension and Double Tension strings shall be taken as given in enclosed drawings. The design of the tower shall be such that it should satisfy all the above conditions when clearances are measured from any live point of the strings. As the Contractor may use & supply insulator strings with disc insulators or long rod insulators or polymer insulators, the tower design shall be such that it satisfies the clearance requirements in that particular case.

1.4.7 Cross arm projections for Dead end towers shall be fixed in such a way that it can accommodate a condition of 15-degree deviation of conductors towards tower at both Left and Right side cross arms on slack span side and 0-15 degree deviation on line side.

1.4.8 Angle of Shielding

The angle of shielding is defined as the angle formed by the line joining the centre lines of the earthwire and outer power conductor in still air at tower supports, to the vertical line through the centre line of the earthwire. Bidders shall design the tower in such a way that the angle of shielding does not exceed 20 deg for all towers. The drop of the earthwire clamp equal to 150 mm should be considered while calculating the minimum angle of protection.



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1.4.9 Mid Span Clearance

The minimum vertical mid span clearance between the earthwire and the nearest power conductor shall not be less than 8.5 metres, which shall mean the vertical clearance between earthwire and the nearest conductor under all temperatures and still air condition in the normal ruling span. Further, the tensions of the earthwire and power conductor, shall be so co-ordinated that the sag of earthwire shall be at least 10% less than that of power conductors under all temperature loading conditions.

1.5 Normal Loading Conditions

1.5.1 Loads at Conductor and Earthwire Points

Employer has calculated the ultimate external loadings at conductor and earthwire/OPGW points and is enclosed along with the specification. The Contractor shall develop the tower designs based on the loadings given by the Employer only.

1.5.2 Wind Loads on Tower Body

The wind load on tower body shall be calculated by the Contractor as per clause 9.1 of IS 802(Part 1/Sec 1):1995. The following data shall be considered for calculating wind load on tower body.

a) Dynamic reference wind pressure shall be considered as 71.5 Kg/m2.

b) Terrain category shall be considered as 2.

c) The angle of incidence of Wind θ (Theta) = 0 Degree.

1.5.3 Maximum Tension

1.5.3.1 Max. tension shall be based on either

a) at 0 deg C with 36 percent full wind pressure, or

b) at 32 deg C with full wind pressure whichever is more stringent.

1.5.3.2 Employer has calculated sag tension calculation for a normal span of 350 meters for the purpose of tower design. Sag tensions calculations are furnished alongwith the specification.

1.5.3.3 The initial conductor and earthwire tension (maximum) at 32ºC and without wind shall be 22% of the ultimate tensile strength of the conductor and 20% of the ultimate tensile strength of the earthwire.

1.5.4 Limiting Tensions of Conductor & Earthwire

The ultimate tension of conductor and earthwire shall not exceed 70 per cent of the ultimate tensile strengths.

1.5.5 Broken Wire Condition

1.5.5.1 Suspension Tower Type DA



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Any one phase (both sub-conductors) or earthwire broken; whichever is more stringent for a particular member.

1.5.5.2 Tension Tower Type DB and DC

Breakage of any two phases (both sub-conductors) on the same side and on the same span or breakage of any one phase (both sub-conductors) and one earthwire on the same side and same span whichever combination is stringent for a particular member.

1.5.5.3 Tower Type DD

Breakage of all the three phases (both sub-conductors) on the same side and on the same span or breakage of two phases (both sub-conductors) and one earthwire on the same side and on the same span, whichever combination is more stringent for a particular member.

1.6 Design of Towers

1.6.1 Design Criteria

Towers shall be designed based on spans and clearances as per Clause 1.3 & 1.4 and loading conditions as per Clause 1.5 above.

1.6.2 Design Temperatures

The following temperature range for the conductors and ground wires shall be adopted for line design:

i) Minimum Temperature : 0 deg.C

ii) Every day temperature of conductor : 32 deg.C

iii) Max. temperature of

a) Conductor : 80 deg.C

b) Earthwire exposed to sun : 53 deg.C

1.6.3 Conductor and Earthwire Configuration

For double circuit towers the three phases shall be in vertical formation. The phase to phase spacing for conductors shall be not less than 4.5 meters vertically. However, the minimum horizontal separation between phase conductors of two circuits shall be 8.4 meters.

1.6.4 Redundant Design

1.6.4.1 All redundant in the tower are to be triangulated.

1.6.4.2 All bracing and redundant members of the towers which are horizontal or inclined up to 15º from horizontal shall be designed to withstand an ultimate vertical load of 1500 N considered acting at centre independent of all other



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loads. The bending moment for designing of redundant members shall be considered as WL/4 irrespective of end connections and continuity. The contractor has to furnish the calculations for the same (where W is ultimate load of 1.5 kN and ‘L’ is the length of redundant from bolt to bolt).

1.6.4.3 All redundant shall be designed individually for 2.5% of maximum axial load of connecting members (i.e. leg members, bracing members etc.) as per drawing no.K-D/220kV/0013. The contractor has to furnish the calculations for the same.

1.6.4.4 Connection of single Redundant to leg member having a section of 110 x 110 x 10 and above shall be done with minimum of 2 bolts.

1.6.5 THICKNESS OF MEMBERS

The minimum thickness of angle sections used in the design of towers, unless otherwise specified elsewhere in this Specification, shall be kept not less than the following values:

a) Main corner leg members including the : 5 mm earthwire peak and main cross arm b) For all other members : 4 mm

1.6.6 BOLTS AND NUTS

1.6.6.1 The minimum bolt spacing and rolled edge distance and sheared edge distance from the centers of bolt holes to be maintained are given in Table 1.3

TABLE 1.3

Diameter of Hole Min. Bolt Min. Rolled Min. Sheared Bolt Diameter Spacing Distance Edge Distance (mm) (mm) (mm) (mm) (mm) ------------------------------------------------------------------------------------------------------

16 17.5 40 20 23

24 25.5 60 33 38

------------------------------------------------------------------------------------------------------

Bolts sizes mentioned above shall only be used. The minimum width of the flanges without bolt holes shall be 30 mm

1.6.6.2 For the purpose of calculating shearing stress and bearing stress for bolts clause 5.4 of IS: 802 (Part-1/Sec 2):1992 shall be referred.

1.6.7 SLENDERNESS RATIO

1.6.7.1 Slenderness ratio for members shall be computed in accordance with clause 6.4 of IS: 802 (Part-1/Sec 2):1992.



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1.6.7.2 Slenderness ratio for compression and tension members shall not exceed the values specified therein.

1.6.7.3 The following maximum limit of the slenderness ratio i.e. the ratio of unsupported length of the section in any plane to the appropriate radius of gyration will be adopted:

VALUE OF KL/R

a) For main corner leg members including the corner members of earthwire peak and the lower corner 120

members of the cross-arms b) For other members having calculated stresses 200

c) For redundant members 250

d) For members having tensile stress only 375

1.6.8 ERECTION STRESS

Where erection stress combined with other permissible co-existent stresses could produce a working stress in any members appreciably above the specified working stress, such other provision are to be made as may be necessary to bring the working stress within the specified limit.

1.6.9 STRUCTURAL ARRANGEMENT OF MEMBERS IN A TOWER

1.6.9. Lifting Points shall be provided in the tension tower and shall be designed for a load of 1020 Kgs assumed as acting at a 600 mm distance from the tip of the cross arm.

1.6.9.2 Internal angle between two members shall not be less than 15 degrees.

1.6.10 Design Calculation and Drawings

1.6.10.1 The following design calculation and drawings are required to be furnished to the Employer:

A) Alongwith the bid:

Detailed design calculations and drawings for DD type tower only.

B) After award of contract:

The Contractor shall submit detailed design of tower & extension alongwith stress diagram / computer output together with sample calculations for few critical members etc., stub templates and loading / rigging arrangement of tower testing to enable the Employer to make a preliminary check regarding structural stability of tower (before) tests.

1.6.10.2 After successful testing of tower and subsequent approval of design, drawings and bill of materials, the Contractor shall furnish the following in



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ten (10) copies to the Employer for necessary distribution with in fifteen(15) days after approval of drawings:

a) Detailed design calculation and drawing for towers and foundations.

b) Detailed structural drawings indicating section size, length of members, sizes of plates along with hole to hole distance & joint details etc.

c) Bill of materials, indicating cutting and bending details against each member.

d) Shop drawings showing all details relevant to fabrication.

e) All the drawings for the tower accessories.

1.6.10.3 The Contractor is required to submit four copies of the drawings as mentioned in clause 1.6.10.2 for Employer’s approval. While submitting the designs, structural drawings bill of materials and any other drawing pertaining to the subject transmission line, the Contractor shall clearly indicate on each drawing NEA Specification No., Name of the transmission line and project , letter reference No. and date on which the submission are made. The same practice is also to be followed while submitting distribution copies.

1.6.10.4 The design and drawings as covered in clause 1.6.10.1 (B) above shall be approved / commented by the Employer as the case may be within twenty eight (28) days of receipt of design / drawings in NEA office. If the design / drawings are commented by the Employer, the Contractor shall submit revised designs / drawings with in fifteen (15) days of date of issue of comments.

1.6.10.5 The Contractor is required to furnish the progress of submissions and approvals of designs and drawings on twenty fifth day of every month till the completion of all the design activities..

The details shall include description of design / drawing, schedule date of submission, actual date of submission schedule date of approval ,actual date of approval, schedule date of submission of distribution copies, actual date of submission of distribution copies, schedule date of tower test, actual date of tower test and ‘Remarks’ column. Provision of six additional columns shall also be made in the above progress report to indicate date of comments issued by the Employer and details of submission of revised designs / drawings.

1.6.10.6 The tower accessories drawings like name plate, danger plate, phase plate, circuit plate, anticlimbing device, step bolt, D-shackle etc. shall also be prepared by the Contractor and shall be submitted to the Employer, in three copies, along with one reproducible, for record. These drawings shall be prepared in A4 size only.

1.6.10.7 All the drawings shall have a proper name plate clearly displaying the name of Employer on right hand bottom corner. The approval for exact format of the



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nameplate shall be obtained by the successful bidder from the Employer for adopting the same on all the drawings. Also all the drawings shall carry the following statement and shall be displayed conspicuously on the drawing:

WARNING: THIS IS PROPRIETORY ITEM AND DESIGN RIGHT IS STRICTLY RESERVED WITH NEPAL ELECTRICITY AUTHORITY (NEA). UNDER NO CIRCUMSTANCES THIS DRAWING SHALL BE USED BY ANYBODY WITHOUT PRIOR PERMISSION FROM NEA IN WRITING.

1.7 Materials

1.7.1 Tower Steel Sections

1.7.1.1 IS Steel Sections of tested quality of conformity with IS:2062:2011 grade E250 (Designated Yield Strength. 250 MPa) and/ or grade E350 (Designated Yield Strength 350 MPa) are to be used in towers, extensions, stubs and stub setting templates. For Snow Zone towers MS & HT Steel Sections shall conform to E250 Grade-C & E350 Grade-C respectively. The Contractor can use other equivalent grade of structural steel angle sections and plates conforming to latest International Standards viz BSEN 10025. However, use of steel grade having designated yield strength more than that of EN 10025 grade S355 JR/JO (designated yield strength 355 MPa) is not permitted, unless otherwise indicated in this specification.

1.7.1.2 Steel plates below 6mm size exclusively used for packing plates/packing washers produced as per IS : 1079 (Grade-0) are also acceptable. However, if below 6mm size plate are used as load bearing plates viz gusset plates , joint splices etc. the same shall conform to IS : 2062 or equivalent standard meeting mechanical strength/metallurgical properties corresponding to grade E250 or above grade (designated yield strength not more than 355MPa), depending upon the type of grade incorporated into design. Flats of equivalent grade meeting mechanical strength/ metallurgical properties may also be used in place of plates for packing plates/ packing washers. The chequered plates shall conform to IS : 3502. SAILMA 350HI grade plate can also be accepted in place of HT plates (EN 10025 grade S355 JR/JO / IS 2062:2011 – grade E350, as applicable) provided SAILMA 350HI grade plate meet all the mechanical properties of plate as per EN 10025 grade S355 JR/JO (designated yield strength 355 MPa) / IS 2062: 2011 – grade E350.

1.7.1.3 For designing of towers, preferably rationalised steel sections shall be used. During execution of the project, if any particular section is not available, the same shall be substituted by higher section at no extra cost to Employer and the same shall be borne by the Contractor. However, design approval for such substitution shall be obtained from the Purchaser before any substitution.



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1.7.2 Fasteners: Bolts, Nuts and Washers

1.7.2.1 All tower members shall be joined together with Bolts and nuts. All hexagonal bolts and nuts shall conform to IS-12427. They shall have hexagonal head and nuts, the heads being forged out of the solid, truly concentric, and square with the shank, which must be perfectly straight.

All bolts and nuts shall be galvanised as per IS:1367 (Part-13) / IS:2629 .

1.7.2.2 The bolt shall be of 16 / 24 mm diameter and of property class 5.6 as specified in IS:1367 (Part-III) and matching nut of property class 5.0 as specified in IS:1367 (Part-VI).

1.7.2.3 Bolts up to M16 and having length up to 10 times the diameter of the bolt should be manufactured by cold forging and thread rolling process to obtain good and reliable mechanical properties and effective dimensional control. The shear strength of bolts for 5.6 grade should be 310 MPa minimum as per IS: 12427. Bolts should be provided with washer face in accordance with IS: 1363 (Part-I) to ensure proper bearing.

1.7.2.4 Nuts for hexagonal bolts should be double chamfered as per the requirement of IS: 1363 Part-III. It should be ensured by the manufacturer that nuts should not be over tapped beyond 0.4mm oversize on effective diameter for size up to M16.

1.7.2.5 Fully threaded bolts shall not be used. The length of bolts shall be such that the threaded portion will not extend into the place of contact of the members.

1.7.2.6 All bolts shall be threaded to take the full depth of the nuts and threaded for enough to permit firm gripping of the members, but not further. It shall be ensured that the threaded portion of each bolt protrudes not less than 3mm and not more than 8mm when fully tightened. All nuts shall fit tight to the point where the shank of the bolt connects to the head.

1.7.2.7 Flat and tapered washers shall be provided wherever necessary. Spring washers shall be provided for insertion under all nuts. These washers shall be steel electro-galvanised, positive lock type and 3.5mm in thickness for 16mm diameter bolt and 4.5 mm for 24 mm bolt.

1.7.2.8 To avoid bending stress in bolts or to reduce it to minimum, no bolt shall connect aggregate thickness of members more than three (3) times its diameter.

1.7.2.9 The bolt positions in assembled towers shall be as per IS: 5613 (Part-II / Section 2) -1976.

1.7.2.10 Bolts at the joints shall be so staggered that nuts shall be tightened with spanners without fouling.

1.7.2.11 To ensure effective in-process Quality control it is desirable that the manufacturer should have in house testing facility for all tests like weight of zinc coating, shear strength and other tests etc. The manufacturer should



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also have proper Quality Assurance System which should be in line with the requirement of this specification and IS: 14000 series Quality System Standard.

1.8 Tower Accessories

Arrangement shall be provided for fixing of all tower accessories to the tower at a height between 2.5 meters and 3.5 meters above the ground level.

1.8.1 Step Bolts & Ladders

Each tower shall be provided with step bolts conforming to IS: 10238 of not less than 16mm diameter and 175 mm long spaced not more than 450mm apart and extending from 2.5 meters above the ground level to the top of the tower. However, the head diameter shall be 50mm as indicated in the enclosed drawing. For double circuit tower the step bolt shall be fixed on two diagonally opposite legs up to top of the towers. Each step bolt shall be provided with two nuts on one end to fasten the bolt securely to the tower and button head at the other end to prevent the feet from slipping away. The step bolts shall be capable of withstanding a vertical load not less than 1.5 KN. For special towers, where the height of the super structure exceeds 50 meters, ladders along with protection rings as per the Employer’s approved design shall be provided in continuation of the step bolts on one face of the tower from 30 meters above ground level to the top of the special structure. From 2.5m to 30m height of super structure step bolts shall be provided. Suitable platform using 6mm thick perforated chequered plates along with suitable railing for access from step bolts to the ladder and from the ladder to each cross-arm tip and the ground wire support shall also to be provided. The platform shall be fixed on tower by using counter-sunk bolts.

1.8.2 Insulator String Attachments

a) For the attachment of suspension Insulator string, a suitable dimensioned swinging hanger on the tower shall be provided so as to obtain specified clearances under respective swinging condition of the strings. The hanger, extensions links, D-shackles etc. as required and considered in the design of the tower shall have minimum ultimate tensile strength of 240KN for double suspension string for 220KV suspension towers. The design and supply of hanger, D-shackles, strain plates etc. are also in the scope of Contractor.

b) At tension towers, strain plates of suitable dimensions under each cross-arm tip, shall be provided for taking the hooks or D-shackles of the tension insulator strings. Full details of the attachments shall be provided by the contractor. To achieve requisite clearances, if the design calls for providing extra D-shackles, link plate etc. before connecting the insulator string the same shall be supplied by the Contractor.



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1.8.3 Earth wire Clamp Attachments a) Suspension Clamps

Earth wire suspension clamps will be supplied by the contractor. The detailed drawing shall be submitted by the Contractor for Employer’s approval. The Contractor shall also supply U- bolts, D-shackles wherever required.

b) Tension Clamps

Earth wire peaks of tension towers shall be provided with suitable plates to accommodate the shackle of tension clamps. The contractor shall also supply the U-bolts wherever required and take Employer’s approval for details of the attachments before the mass fabrication.

1.8.4 Anti Climbing Device

Barbed wire type anti climbing device, as per enclosed drawing shall be provided and installed by the Contractor for all towers. The barbed wire shall conform to IS-278 (size designation A1). The barbed wires shall be given chromating dip as per procedure laid down in IS: 1340.

1.8.5 Danger, Number, Circuit and Phase plate

Danger plates, Number plates, Circuit plates and Phase plates shall be provided and installed by the Contractor.

a) Each tower shall be fitted with a danger plate, number plate and one set of phase plates for double circuit tower. Circuit plates shall be provided on all the Double Circuit towers.

b) The letters, figures and the conventional skull and bones of danger plates shall conform to IS-2551 and shall be in a signal red on the front of the plate.

c) The corners of the danger, number and circuit plates shall be rounded off to remove sharp edges.

d) The letters of number and circuit plates shall be red enameled with white enameled background.

1.8.6 Aviation Requirements

1.8.6.1 Aviation requirements viz Span marker, night marker (obstruction light) and painting of towers conforming to IS: 5613 shall be in the scope of Contractor, wherever indicated in BPS.

1.8.6.2 Night Markers (Obstruction lights)

1.8.6.2.1 The scope of night markers covers the design, manufacture, testing at manufacturers works, if any, supply, delivery, erection, testing and commissioning of medium intensity, low intensity, lights along with storage



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battery & solar panel, control panel, cables, clamps other accessories etc. as per the provision of IS-5613 (Part-II/ section-I), 1989, amendment no. 1, July’94 regarding night & day visual aids for denoting transmission line structures as per the requirement of directorate of flight safety.

1.8.6.2.2 The detail of each component of medium intensity, low intensity lights & associated accessories to be provided on the towers shall be as per the technical specifications given in the preceding clauses and IS/ICAO, International Standards recommended practices.

1.8.6.2.3 One set of Aviation Lights shall consist of one medium intensity light & two/four (as applicable) low intensity lights along with all accessories such as solar panel, control panel, batteries, cables etc.

1.8.6.2.4 Medium Intensity Light

Medium Intensity light shall be provided on the top of each tower. The medium light should have night time intensity as per ICAO requirements in international Standards Recommended Practices. The light on top of the structure should flash at the rate of 20 sequences per minute. The effective intensity during night time for the medium flashing light shall be 1600 CD. The light shall conform to ICAO requirements/BS 3224a and shall have weather protection conforming to IP-55.

The above lights conforming to ICAO specifications flashing red lights shall be DC operated through a suitably sized battery bank at the operating voltage 12V/24V DC. The burning life of the lamps shall be maximum possible in view of the maintenance hazard of H.T. live but in no case it should be less than 15,000 burning hours. In case of failure of the lamp before 15,000 burning hours, the same shall have to be replaced by the Contractor free of cost even if the pendency of contract expires. The light shall be equipped with radio suppression facility conforming to BS800 in order to avoid any interference with signals of PLCC etc.

1.8.6.2.5 Low Intensity Lights

Two/four (as applicable) nos. of low intensity lights are required to be put on each of the towers. Placement drawing for the same shall be submitted by the bidder Contractor.

The light shall be stationary lamp with minimum effective intensity of 10 CD. of red light. The lamps shall conform to the ICAO requirement/relevant BS and shall have weather protection of minimum IP-55 class.

Two/four nos. of L.I. lamp required for each tower shall be operated through a suitable size common battery bank solar panel as per the requirement of operating voltage and load current of the type of lamps being offered.

The burning life of the lamps shall be maximum possible in view of the maintenance hazard of H.T live line, but in no case it should be less than 15,000 burning hours. In case of failure of the lamp before 15,000 hrs, the



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same shall have to be replaced by the Contractor free of cost even if the pendency of contract expires. Performance certificate of the lamps to be offered shall be furnished by the Contractor.

The low intensity lamp shall not generate any R.F. which can interfere with the PLCC signals.

1.8.6.2.6 Storage Battery

Storage Battery required for the above purpose shall be sealed maintenance free, valve regulate lead acid and suitable for mounting on the top of the transmission line towers. Contractors shall offer the most optimum capacity of the Battery Bank at 120 hour discharge rate (considering 80 % percentage usage) matching with the load requirement of the type of lamps being offered including any power loss in the associated cables. The battery sizing shall conform to JISC 8707/relevant Indian Standard or any other internationally recognized standard. The battery shall be hermetically sealed explosion proof and self-resealing type and free from orientation constraints. The working temperature ranges shall be minimum 0 degree centigrade and maximum 50 degree centigrade. Performance certificate of the offered batteries shall be submitted by the Contractor.

1.8.6.2.7 Battery Box

The battery box suitable for mounting on 220kV power transmission tower shall be robust construction suitable to accommodate desired number of SOLAR BATTERIES WITH proper clearance between the batteries. The sides and the top of the battery box shall be made from MS sheets not less than 14 SWG thickness duly mounted on MS angle frame. The bottom of the battery box shall have suitably designed MS structure to freely hold the total weight of the batteries. The batteries should be placed on insulated base with proper drainage holes. Lifting lugs shall be provided. Dust and vermin proof lockable doors shall be provided for safety and easy access to the batteries for the maintenance. The battery box should incorporate the design for proper ventilation system in order to prevent a gas concentration inside the box. The ventilation opening shall be protected against rain/splash water and dust. The inside of the battery box shall be lined with insulating polyurethane plating and the exterior painted with weather proof polyurethane paint. The cable entry into the battery box shall be through suitable cable glands.

1.8.6.2.8 Solar Modules

Solar module required for the system shall be suitable for mounting on the transmission line towers and shall be designed for high performance, maximum reliability and minimum maintenance and shall be installed below bottom cross arms levels. The solar modules shall be IP 55 grade protection class. These should be highly resistant to water, abrasion, nail, impact and other environmental factors.



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These should be placed on the tower at a most optimum angle so as to harness the maximum solar energy and facilitate self cleaning and shall conform to relevant Indian/International Standards.

Module mounting frames shall be weather proof suitable for mounting on tall towers. Details of mounting frames shall be furnished by the Contractor.

Junction box shall be provided with weather proof hinged lid with provision for cable glands entry and protections grade of class IP-55.

The Contractor shall submit the basis of selecting the numbers of solar modules.

The provision for design, supply & erection of mounting arrangements for photovoltaic modules on the transmission towers in a suitable manner to harness maximum solar energy shall be in the scope of the Contractor.

Provision for design, supply & erection of resting platform for the erection of battery bank in a closed enclosure with safety arrangement on the transmission towers shall also be in the scope of the Contractor the design and load consideration for safety of towers due to additional plate form shall be kept in view while designing, selecting the above.

1.8.6.2.9 Control Panels

Control panels shall consist of solar charge controller, flasher unit, sensor, isolator, MCB, Voltmeter, Ammeter and other control gears. Panel enclosure shall be fabricated out of 14 SWG CRCA sheet and thoroughly treated and painted. Suitable neoprene rubber gasket and pad locking device shall be provided and the protection class shall be of IP-55 class.

The Solar charge controller shall be most efficient and preferably fully solid state. It shall be provided with protection to load against increase in temperature, Surge, automatic low voltage and automatic disconnection and reconnection during high inrush current and normalcy respectively.

The flash regulator shall be provided for regulating light flashing. The same shall be completely solid state and provided with flash rate set points. The protection against overload current shall also be provided.

Necessary sensor/timer shall be provided in the system to “switch on” the light automatically in the evening and poor visibility period and switch off the same during day time and normal visibility period.

1.8.6.2.10 Cables, Cable Glands, Conduits and Accessories

The cable to be supplied and erected shall be of multi strands copper conductor, weather proof, PVC insulated PVC sheathed, armoured 1.1 KV grade. The same shall conform to IS:1554.

All the cable accessories such as thimble, glands etc. shall be in the scope of supply and erection of the Contractor.



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Supply and erection of all the PVC conduits and accessories shall be in the scope of the contract. All the conduit and accessories shall be as per the relevant ISS or ISI brand.

The inter-connection cable/conduit will be clamped in a secured manner with the tower members and any interconnection should be made only inside the environmentally protected junction box.

1.8.6.2.11 Earthing All the installations on the tower shall be securely and properly earthed with

the tower body by using flexible copper braided wire. Cost of earthing material shall deemed to be included in the total cost.

1.9 Tower Fabrication

The fabrication of towers shall be in conformity with the following:

1.9.1 Except where hereinafter modified, details of fabrication shall conform to IS: 802 (Part-II) or the relevant international standards.

1.9.2 Butt splices shall be used and the inside angle and outside plate shall be designed to transmit the load. Inside cleat angle shall not be less than half the thickness of the heavier member connected plus 2mm. Lap splice may be used for connecting members of unequal sizes and the inside angle of lap splice shall be rounded at the heel to fit the root radius of the outside angle. All the splices shall develop full strength in the member connected through bolts. Butt as well as lap splice shall be made as above and as close to the main panel point as possible.

1.9.3 Joints shall be so designed as to avoid eccentricity as far as possible. The use of gusset plates for joining tower members shall be avoided as far as possible. However, where the connections are such that the elimination of the gusset plates would result in eccentric joints, gussets plates and spacers plates may be used in conformity with modern practices. The thickness of the gusset plates, required to transit stress shall not be less than that of members connected.

1.9.4 The use of filler in connection shall be avoided as far as possible. The diagonal web members in tension may be connected entirely to the gusset plate wherever necessary to avoid the use of filler and it shall be connected at the point of intersection by one or more bolts.

1.9.2 The tower structures shall be accurately fabricated to connect together easily at site without any undue strain on the bolts.

1.9.3 No angle member shall have the two leg flanges brought together by closing the angle.

1.9.4 The diameter of the hole shall be equal to the diameter of bolt plus 1.5mm.



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1.9.5 The structure shall be designed so that all parts shall be accessible for inspection and cleaning. Drain holes shall be provided at all points where pockets of depression are likely to hold water.

1.9.6 All identical parts shall be made strictly inter-changeable. All steel sections before any work is done on them, shall be carefully leveled, straightened and made true to detailed drawings by methods which will not injure the materials so that when assembled, the adjacent matching surfaces are in close contact throughout. No rough edges shall be permitted in the entire structure.

1.9.7 Drilling and Punching

1.9.7.1 Before any cutting work is started, all steel sections shall be carefully straightened and trued by pressure and not by hammering. They shall again be trued after being punched and drilled.

1.9.7.2 Holes for bolts shall be drilled or punched with a jig but drilled holes shall be preferred. The punching may be adopted for thickness up to 16mm. Tolerances regarding punched holes are as follows:-

a) Holes must be perfectly circular and no tolerances in this respect are permissible.

b) The maximum allowable difference in diameter of the holes on the two sides of plates or angle is 0.8mm. i.e. the allowable taper in a punched holes should not exceed 0.8mm on diameter.

c) Holes must be square with the plates or angles and have their walls parallel.

1.9.7.3 All burrs left by drills or punch shall be removed completely. When the tower members are in position the holes shall be truly opposite to each other. Drilling or reaming to enlarge holes shall not be permitted.

1.9.8 Erection mark

1.9.8.1 Each individual member shall have erection mark conforming to the component number given to it in the fabrication drawings. The mark shall be marked with marking dies of 16mm size before galvanizing and shall be legible after galvanizing.

1.9.8.2 Erection Mark shall be A-BB-CC-DDD

A = Employer’s code assigned to the Contractors- Alphabet

BB = Contractor’s Mark-Numerical

CC = Tower Type Alphabet.

DDD = Number mark to be assigned by Contractor - Numerical.

Erection mark for high tensile steel members shall be prefixed by the letter “H”



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1.10 Quantities and weights

1.10.1 The provisional quantity of towers & extensions are mentioned in the respective Schedule of Prices. Final quantities shall be determined after completion and approval of the tower spotting & check survey. The final quantities of tower shall be confirmed by the Employer based on the required quantities of various towers & extensions furnished by the Contractor after completion of final tower spotting & check survey. Hence, it will be responsibility of the Contractor to intimate the exact requirements of all towers and various line materials required for line immediately after the tower spotting & check survey.

The Employer reserves the right to order the final quantities including reasonable quantities of spares for which the rates quoted in the Bid shall be valid. Regarding quantity variation, the provisions of relevant clauses of SCC shall apply.

1.10.2 The estimated unit weight of each type of galvanized towers, stubs and leg extensions shall be furnished by the bidder. The weight of tower shall mean the weight of tower calculated by using the black sectional (i.e. un galvanized) weight of steel members of the size indicated in the approved fabrication drawings and bill of materials, without taking into consideration the reduction in weights due to holes, notches and bevel cuts etc. but taking into consideration the weight of the anticlimbing devices, D shackles, hangers, strain plates, pack plates, gusset plates and pack washers etc. The weight of gusset plates shall mean the weight of its circumscribing rectangle, without taking into consideration the reduction in weights due to holes, notches etc. For bolts and nuts along with spring washers and step bolts, the weight per tower shall be calculated from the bolt schedule applicable to each type of towers, stubs and leg extensions as approved by the Employer. The rate quoted by the bidder for supply of tower / tower parts is deemed to be inclusive of galvanising charges including the cost of zinc.

1.10.3 The contractor is permitted to get inspected and supply up to 2.5% extra

fasteners to take care of losses during erection. No payment shall be admissible for these extra supplies.

1.11 Galvanising 1.11.1 Fabricated Tower Parts & Stubs The tower parts, stubs and pack washers shall be hot dip galvanized .The

galvanization shall be done as per requirements of IS: 4759 after all fabrication work is completed. The contractor shall also take guidelines from the recommended practices for hot dip galvanizing laid down in IS 2629 while deciding and implementing galvanizing procedure. The mandatory requirements however, are specified herein.



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Unless otherwise specified the fabricated tower parts and stubs shall have a

minimum overall Zinc coating of 610 gms per sq. m of surface except for plates below 5mm which shall have Zinc coating of 460 gms per sq. m of surface. The average zinc coating for sections 5mm & above shall be maintained as 87 microns and that for sections below 5mm shall be maintained as 65 microns.

The zinc coating shall be adherent, reasonably uniform, smooth, continuous

and free from imperfections such as black bare spots, ash rust stains, bulky white deposits / wet storage stains and blisters.

The surface preparation for fabricated tower parts and stubs for hot dip

galvanizing shall be carried out as indicated herein below:

(i) Degreasing & Cleaning of Surface: Degreasing and cleaning of surface, wherever required, shall be carried out in accordance with clause 4.1 of IS 2629-1985. After degreasing the article shall be thoroughly rinsed. However, if acidic degreasers are used rinsing is not required.

(ii) Pickling: Pickling shall be done using either hydrochloric or sulfuric acid as

recommended at clause 4.3 of IS 2629 -1985. The actual concentration of the acids and the time duration of immersion shall be determined by the Contractor depending on the nature of material to be pickled. Suitable inhibitors also shall be used with the acids to avoid over pickling. The acid concentration, inhibitors used, and maximum allowable iron content shall form part of plant standard to be formulated and submitted to Purchaser along with Quality Assurance Program.

(iii) Rinsing: After pickling, the material shall be rinsed, preferably in running

water to remove acid traces, iron particles or any other impurities from the surface. Two rinse tanks are preferable, with water cascading from the second tank to the first to ensure thorough cleaning. Wherever single tank is employed, the water shall be periodically changed to avoid acid contamination, and removal of other residue from the tank.

(iv) Fluxing: The rinsed article shall be dipped in a solution of Zinc ammonium

chloride. The concentration and temperature of the flux solution shall be standardized by the contractor depending on the article to be galvanized and individual circumstances. These shall form part of plant standard to be formulated and submitted to Purchaser along with Quality Assurance Program. The specific gravity of the flux solution shall be periodically monitored and controlled by adding required quantity of flux crystals to compensate for drag-out losses. Free acid content of the flux solution also shall be periodically checked and when it is more than two (2) grams of free acid per litre of the solution, it shall be neutralized. Alternatively, Ph value should be monitored periodically and maintained between 5 to 5.5



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(v) Drying: When dry galvanizing is adopted the article shall be thoroughly dried

after fluxing. For the purpose of drying, the contractor may use hot plate, air oven or any other proven method ensuring complete drying of the article after fluxing and prior to dipping in the molten zinc bath. The drying process shall be such that the article shall not attain a temperature at which the flux shall get decomposed. The article thus dried shall be galvanized before the flux coating picks up moisture from the atmosphere or the flux layer gets damaged or removed from the surface. The drying procedure, time duration, temperature limits, time lag between fluxing, drying, galvanizing etc shall form part of plant standard to be formulated and submitted to Purchaser along with Quality Assurance Program.

(vi) Quality of Zinc: Any one or combination of the grades of zinc specified in IS

209 or IS 13229 or other comparable international standard shall be used for galvanizing. The contractor shall declare the grade(s) of zinc proposed to be used by them for galvanizing. The molten metal in the zinc bath shall contain minimum 98.5 % zinc by mass. It shall be periodically measured and recorded. Zinc aluminum alloy shall be added as per IS 2629.

(vii) Dipping Process: The temperature of the galvanizing bath shall be

continuously monitored and controlled. The working temperature of the galvanizing bath shall be maintained at 450+/ - 10 degree C .The article should be immersed in the bath as rapidly as possible without compromising on safety aspects. The galvanizing bath temperature, immersion angle & time, time duration of immersion, rate of withdrawal etc shall be monitored and controlled depending upon the size , shape, thickness and chemical composition of the article such that the mass of zinc coating and its uniformity meets the specified requirements and the galvanized surface is free from imperfections and galvanizing defects.

(viii) Post Treatment: The article shall be quenched in water. The quench water is

to be changed / drained periodically to prevent corrosive salts from accumulating in it. If water quenching is not done then necessary cooling arrangements should be made. The galvanized articles shall be dipped in chromating solution containing sodium dichromate and sulfuric acid or chromic acid base additive at a predetermined concentration and kept at room temperature to retard white rust attack. The temperature of the chromate solution shall not exceed 65 degree C. The articles shall not be stacked immediately after quenching and dichromating. It shall be ensured that the articles are dry before any further handling operation.

(ix) Storing, Packing and Handling: In order to prevent white rust formation

sufficient care should be exercised while storing handling and transporting galvanized products. The articles shall be stored in an adequately ventilated area. The articles shall be stored with spacers in between them and kept at an inclination to facilitate easy drainage of any water collected on the



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articles. Similar care is to be taken while transporting and storing the articles at site.

The Contractor shall prepare a detailed galvanizing procedure including Flow

Chart with control parameters and all plant standards as required above and submit to Employer for approval as part of Quality Assurance Plan.

1.11.2. Fasteners. For fasteners, the galvanizing shall conform to IS-1367(Part-13). The

galvanizing shall be done with centrifuging arrangement after all mechanical operations are completed. The nuts, may however be tapped (threaded) or rerun after galvanizing and the threads oiled .The threads of bolts & nuts shall have a neat fit and shall be such that they can be turned with finger throughout the length of the threads of bolts and they shall be capable of developing full strength of bolts. Spring washers shall be electro galvanized as per Grade-IV of IS-1573.

1.12 Earthing

The Contractor shall measure the tower footing resistance (TFR) of each tower after it has been erected and before the stringing of the earth wire during dry weather. Each tower shall be earthed. The tower footing resistance shall not exceed 10 ohms. Pipe type earthing and counter poise type earthing wherein required shall be done in accordance with the latest additions and revisions of:

IS: 3043 Code of practice for Earthing.

IS: 5613 Code of practice for Design, Installation and maintenance (Part-II/Section-2) of overhead power lines.

1.12.1 The details for pipe & counterpoise type earthing are given in the drawings enclosed with these specifications.

1.12.2 For counterpoise type earthing the earthing will vary depending on soil resistivity. For soil resistivity less than 1500 ohms-meter, earthing shall be established by providing 4 lengths of 30m counterpoise wire. Otherwise, for soil resistivity greater than 1500 ohms meter earthing shall be established by providing 4 length of 70m counterpoise wire. In case resistivity does not come down less than 10 ohms even after providing 70 m counterpoise wire, Contractor shall submit a statement in this regard to Employer to know further course of action.

1.12.3 The provisional quantities for pipe type earthings and counterpoise earthing are furnished in the Price Schedule. The bidders are required to quote unit rates for the same in appropriate Price Schedule. The quoted price shall include fabrication, supply and installation of earthing material including



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supply of coke, salt etc. In case of counterpoise type earthing, the quotation shall be based on 120 meters of wire per tower.

1.12.4 Earthing for River Crossing Towers /Pile foundation

Galvanised earthing strip of flat 50 x 6 mm is to be provided in two legs of tower for each location with proper arrangement of connecting these strips by 16mm bolts shall be provided in the stubs. For pile foundation, the strip has to be taken up to scour level along the concrete of pile foundations. Only bolted connections are allowed for connecting this strip to achieve desired length. Contractor shall submit the detailed drawing for approval of Owner before installations.

1.13 Inspection and Tests

1.13.1 General

All standard tests, including quality control tests, in accordance with appropriate Indian / International Standard, shall be carried out unless otherwise specified herein.

1.13.2 Inspection

In addition to the provision of GCC and Cl.1.7.3 of Section II of this Specification, the following shall also apply:

1.13.2.1 a) The Contractor shall keep the Purchaser informed in advance about the time of starting and of the progress of manufacture and fabrication of various tower parts at various stages, so that arrangements could be made for inspection.

b) The acceptance of any part of items shall in no way relieve the Contractor of any part of his responsibility for meeting all the requirements of the Specification.

1.13.2.2 The Employer or his representative shall have free access at all reasonable

times to those parts of the Contractor’s works which are concerned with the fabrication of the Employer’s material for satisfying himself that the fabrication is being done in accordance with the provisions of the Specification.

1.13.2.3 Unless specified otherwise, inspection shall be made at the place of manufacture prior to dispatch and shall be concluded so as not to interfere unnecessarily with the operation of the work.

1.13.2.4 Should any member of the structure be found not to comply with the supplied design, it shall be liable to rejection. No member once rejected shall be resubmitted for inspection, except in cases where the Purchaser or his authorised representative considers that the defects can be rectified.

1.13.2.5 Defect which may appear during fabrication shall be made good with the consent of, and according to the procedure proposed by the Contractor and approved by the Employer.



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1.13.2.6 All gauges and templates necessary to satisfy the Purchaser shall be supplied by the Contractor.

1.13.2.7 The specified grade and quality of steel shall be used by the Contractor. To ascertain the quality of steel used, the inspector may at his discretion get the material tested at an approved laboratory.

1.14 Tower Load Tests

1.14.1 Testing of Tower

A Galvanized tower of each type complete with 9 M extension shall be subjected to design and destruction tests by first applying test loads applied in a manner approved by the Employer. The tower shall withstand these tests without showing any sign of failure or permanent distortion in any part. Thereafter the tower shall be subjected to destruction by increasing the loads further in an approved manner till it fails. The tower shall be tested for all the conditions considered for the design of tower. The Contractor shall submit to the Employer, for approval, the detailed programme and proposal for testing the towers showing the methods of carrying out the tests and manner of applying the loads. After the Employer has approved the test procedures and programmes the Contractors will intimate the Employer about carrying out the tests at least 30 days in advance of the scheduled date of tests during which the Employer will arrange to depute his representative to be present at the time of carrying out the tests. Six copies of the test reports shall be submitted. The Contractor shall submit one set of shop drawings alongwith the bill of materials at the time of prototype tower testing for checking the tower material. Further at the time of submitting test report, the contractor has to submit the final drawings of shop drawings and Bill of materials for Employer’s reference and record. The type testing charges shall be released only after approval of test report, structural drawings, bill of material and shop drawings of tower.

1.14.1.1 In case of premature failure the tower shall be retested and steel already used in the earlier test shall not be used again. However, in case of minor failures, the contractor can replace the members with higher section and carry out the testing. The Contractor shall provide facilities to the Employer or their representatives for inspection of materials during manufacturing stage and also during testing of the same.

1.14.1.2 In case of any premature failure even during waiting period, the tower is to be retested with rectified members. However, if the failures are major in nature and considerable portion of tower is to be re-erected, in such cases all the tests which has been carried out earlier are required to be re-conducted again in compliance with Specification.

1.14.1.3 No part of any tower subject to test shall be allowed to be used on the line. The price for the tower tests will be quoted after allowing rebate for the scrap value of the tower material which will be retained by the Contractor.



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1.14.1.4 The Contractor shall ensure that the specification of materials and workmanship of all towers actually supplied conform strictly to the towers which have successfully under gone the tests. In case any deviation is detected, the Contractor shall replace such defective towers free of cost to the Employer. All expenditure incurred in erection, to and fro transportation and any other expenditure or losses incurred by Employer on this account shall be full born by the Contractor. No extension in delivery time shall be allowed on this account.

1.14.1.5 Each type of tower to be tested shall be a full scale prototype galvanized tower and shall be erected vertically on rigid foundation of the stub protruding above ground level as provided in the design/drawing between ground level and concrete level. This portion of the stub shall be kept un-braced while testing. The tower erected on test bed shall not be out of plumb by more than 1 in 360.

1.14.1.6 All the measuring instruments shall be calibrated in systematic / approved manner with the help of standard weight / device. Calibration shall be done before commencing the test of each tower up to the maximum anticipated loads to be applied during testing.

1.14.1.7 The suspension tower is to be tested with an arrangement similar to ‘I’ string. The tension tower is to be tested with strain plate as per approved design / drawings.

1.14.1.8 The sequence of testing shall be decided by the Employer at the time of approving the rigging chart / test data sheet.

1.14.1.9 The Employer may decide to carry out the tensile test, bend test etc. as per the relevant IS on few members of the test tower after completion of the test or in case of any premature failure. The Contractor shall make suitable arrangement for the same without any extra cost to the Employer.

1.14.1.10 Prefix ‘T’ shall be marked on all members of test tower in addition to the Mark No. already provided.

1.14.2 Method of Load Application

1.14.2.1 Loads shall be applied according to the approved rigging arrangement through normal wire attachments angles on bent plates.

1.14.2.2 The various types of loads, transverse, vertical and longitudinal shall be applied in such a way that there is no impact loading on the tower due to jerks from the winches.

1.14.2.3 All the loads shall be measured through a suitable arrangement of strain devices or by using weights. Positioning of the strain devices shall be such that the effect of pulley friction is eliminated. In case the pulley friction cannot be avoided, the same will be measured by means of standards weights and accounted for in the test loads.



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1.14.3 Tower Testing Procedure

The procedure for conducting the tower test shall be as follows:

1.14.3.1 Bolt Slip Test

In a bolt slip test the test loads shall be gradually applied up to the 50% of design loads under normal condition, kept constant for two (2) minutes at that loads and then released gradually.

For measurement of deflection the initial and final readings on the scales(in transverse & longitudinal directions) before application and after the release of Loads respectively shall be taken with the help of theodolite. The difference between readings gives the values of the bolt slip.

1.14.3.2 Normal Broken Wire Load Tests

All the loads, for a particular load-combination test, shall be applied gradually upto the full design loads in the following steps and shall also be released in the similar manner:

25 percent,

50 percent,

75 per cent,

90 percent,

95 percent and

100 percent

1.14.3.3 Observation Periods

Under normal and broken wire load tests, the tower shall be kept under observation for sign of any failure for two minutes (excluding the time of adjustment of loads) for all intermediate steps of loading up to and including 95 percent of full design loads.

For normal, as well as broken wire tests, the tower shall be kept under observation for five (5) minutes (excluding the time for adjustment of loads) after it is loaded up to 100 percent of full design loads.

While the loading operations are in progress, the tower shall be constantly watched, and if it shows any tendency of failure anywhere, the loading shall be immediately stopped, released and then entire tower shall be inspected. The reloading shall be started only after the corrective measures are taken.

The structure shall be considered to be satisfactory, if it is able to support the specified full design loads for five (5) minutes, with no visible local deformation after unloading (such as bowing, buckling etc.) and no breakage of elements or constitute parts.



28

Ovalization of holes and permanent deformation of bolts shall not be considered as failure.

1.14.3.4 Recording

The deflections of the tower in transverse and longitudinal directions shall be recorded at each intermediate and final stage of normal load and broken wire load tests by means of a theodolite and graduated scale. The scale shall be of about one meter long with marking up to 5 mm accuracy.

1.14.3.5 Destruction Test

The destruction test shall be carried out under normal condition or broken wire condition. Under which load condition the destruction test is to be carried out shall be intimated to the contractor at the time of approving rigging chart / test data sheet.

The procedure for application of load for normal/broken wire test shall also be applicable for destruction test. However, the load shall be increased in steps of five (5) per cent after the full design loads have been reached.

1.15 Packing

1.15.1 Angle section shall be wire bundled.

1.15.2 Cleat angles, gusset plates, brackets, fillet plate, hanger and similar loose pieces shall be tied and bolted together in multiples or securely wired through holes.

1.15.3 Bolts, nuts washers and other attachments shall be packed in double gunny bags accurately tagged in accordance with the contents.

1.15.4 The packing shall be properly done to avoid losses & damages during transit. Each bundle or package shall be appropriately marked.

1.16 Standards

1.16.1 The design, manufacturing, fabrication, galvanising, testing, erection procedure and materials used for manufacture and erection of towers, design and construction of foundations shall conform to the following Indian Standards (IS) / International Standards which shall mean latest revisions, with amendments / changes adopted and published, unless specifically stated otherwise in the Specification. In the event of supply of material conforming to Standards other than specified, the Bidder shall confirm in his bid that these Standards are equivalent to those specified. In case of award, salient features of comparison between the Standards proposed by the Bidder and those specified in this document will be provided by the Contractor to establish their equivalence.

1.16.2 The material and services covered under these specifications shall be performed as per requirements of the relevant standard code referred



29

hereinafter against each set of equipment and services. Other internationally acceptable standards which ensure equal or higher performance than those specified shall also be accepted.

Sl. No.

Indian Standard

Title International Standard

1. IS:209-1992 Specification for Zinc ISO/R/752 ASTM B6

2. IS 278-1991 Galvanised Steel Barbed wire

ASTM A131

3. IS 800-1991 Code of Practice for General Building Construction in Steel

CSA 6.1

4(a). IS:802(Part 1) Sec 1-1995 Sec 2-1992

Code of Practice for General Building Construction in Steel in Overhead Transmission Line Tower :

Materials, loads and Permissible Stress

Section- 1: Materials and loads

Section-2 : Permissible stresses.

ASCE 52 IEC 826 BS 8100

4(b). IS:802(Part 2)-1990

Code of Practice for use of structural steel in Overhead Transmission Line :

Fabrication, Galvanising, inspection & Packing

ASCE 52

4(c). IS:802(Part 3)-1990

Code of Practice for use of structural steel in Overload Transmission Line:

Tower testing

ASCE 52 IEC 652

5. IS:808-1991 Dimensions for Hot Rolled Steel Beam, Column, Channel and Angle Sections.

6. IS:875-1992 Code of Practice for Design Loads (other than Earthquakes) for Buildings and Structures.

7. IS:1363-1990 Hexagon Nuts (size range M5 to M36)

8. IS:1367-1992 Technical Supply Conditions for Threaded Steel/ Fasteners

9. IS:1477-1990 Code of practice for Painting of Ferrous Metals in Buildings:

Part-I: Pre-treatment Part-II: Painting.

10. IS:1573-1991 Electro-Plated Coatings of inc on iron



30

Sl. No.

Indian Standard


and Steel

11. 10. IS:1852-1993 Rolling and Cutting Tolerances of Hot Rolled Steel Products

12. 11. 10. IS-1893-1991 Criteria for Earthquake Resistant Design of Structures

IEEE 693

13. 12. 11. 10. IS:2016-1992 Plain Washers ISO/R887 ANSIB18-22.1

14. 13. 12. 11. 10. IS:2062-1992 Steel for general structural purposes

15. 13. 12. 11. 10. IS:2074-1992 Ready Mixed Paint. Air Drying, Oxide. Zinc Chrome, Priming Specification.

16. 13. 12. 11. 10. IS:2551-1990 Danger Notice Plates

17. 16. 13. 12. 11. 10. IS:2629-1990 Recommended Practice for Hot Dip Galvanising of iron and steel.

18. 17. 16. 13. 12. 11. 10. IS:2633-1992 Method of Testing Uniformity of Coating of Zinc Coated Articles

ASTM A123 CSA G164

19. 18. 17. 16. 13. 12. 11. 10. IS:3043-1991 Code of Practice for Earthing

20. 18. 17. 16. 13. 12. 11. 10. IS:3063-1994 Single coil Rectangular section Spring Washers for Bolts, Nuts Screws

DIN-127

21. 18. 17. 16. 13. 12. 11. 10. IS:3757-1992 High Strength Structural Bolts

22. 18. 17. 16. 13. 12. 11. 10. IS:4759-1990 Specification for Hot zinc coatings on structural steel and other Allied products

23. 18. 17. 16. 13. 12. 11. 10. IS:5369-1991 General Requirements for Plain Washers

24. 23. 18. 17. 16. 13. 12. 11. 10. IS:5613-1993 Code of Practice for Design installation and Maintenance of Overhead Power Lines

Section-1: Design Part 2,

Section-2: Installation and Maintenance

25. 23. 18. 17. 16. 13. 12. 11. 10. IS:6610-1991 Specification for Heavy Washers for Steel structures

26. 25. 23. 18. 17. 16. 13. 12. 11. 10. IS:6623-1992 High Strength Structural Nuts

27. 25. 23. 18. 17. 16. 13. 12. 11. 10. IS:6639-1990 Hexagon Bolts for Steel Structure. ASTM A394 ASTM A90

28. 25. 23. 18. 17. 16. 13. 12. 11. 10. IS:6745-1990 Method for Determination of weight of ASTM A90



31

Sl. No.

Indian Standard


Zinc coated iron and Steel Articles.

29. IS:8500-1992 Specification for Weldable Structural Steel (Medium & High Strength Qualities)

30. 29. IS:10238-1989 Step Bolts for Steel Structures

31. 29. IS:12427-1988 Bolts for Transmission Line Towers

32. 29. Indian Electricity Rules.

33. 29. Publication No. 19(N)/700

Regulation for Electrical Crossing of Railway Tracks

The standards mentioned above are available from

Reference Abbreviation

Name and Address

BIS/IS Beureau Of Indian Standards. Manak Bhavan, 9, Bahadur Shah Zafar Marg, New Delhi - 110001. INDIA

ISO International Organisation for Standardization. Danish Board of Standardization Danish Standardizing Sraat, Aurehoegvej-12 DK-2900, Heeleprup, DENMARK.

CSA Canadian Standard Association 178, Rexadale Boulevard, Rexdale (Ontario) Canada, M9W 1R3

DIN Deutsches Institute fiir Normung, Burggrafenstrassee 4-10 Post Farh 1107 D-1000, Berlin 30 GERMANY

ASTM American Society for testing and Material 1916 Race Street Philadelphia. PA 1903-1187 USA



32

Indian electricity Rules Regulation for electricity crossing of railway Tracks

Kitab Mahal Baba Kharak singh Marg New Delhi-110001 INDIA

ASTM American Society of civil Engineers 345 East 47th Street New York, NY 10017-2398 USA

IEEE Institute of Electrical and Electronics Engineers 445 Hoes LanePiscataway, NJ

0085-1331, USA

IEC International Electro technical Commission, Bureau Central de la Commission, electro Technique international, 1 Rue de verembe, Geneva SWITZERLAND



33

2.0 Foundations 2.1 The foundation shall generally be of open cast type. Reinforced Cement

concrete footing shall be used for all types of towers in conformity with the present day practices and the specification laid herein. Footings for all the four legs (without unequal chimney extension) of the tower and their extension shall be similar, irrespective of down thrust and uplift.

2.2 Foundation includes supply of all labour, tools & machineries, materials such

as cement, sand, coarse aggregates and reinforcement steel. Rates quoted for foundations in appropriate schedules shall include transportation of construction materials to site, excavation, stub setting, concreting, reinforcement, shoring, shuttering, dewatering, stock piling, dressing, curing, backfilling the foundation after concreting with excavated / borrowed earth (irrespective of leads), consolidation of earth and carriage of surplus earth to the suitable point of disposal as required by the Employer or any other activities related to completion of foundation works.

2.3 Classifications of Foundations

Classification of foundations and design of foundation depend upon the type of soil, subsoil water level and the presence of surface water which have been classified as follows:

2.3.1 Normal dry

To be used for locations where normal dry cohesive or non-cohesive soils are met. Foundations in areas where surface water encountered from rain runoff shall also be classified as normal dry.

2.3.2 Sandy Dry Soil

To be used for locations where cohesion less pure sand or sand with clay content less than 10% met in dry condition. If the clay content is more than 10 % met in dry condition, the foundation shall be classified as Normal Dry.

2.3.3 Wet

To be used for locations where sub-soil water table is met between 1.5 meters from ground level and the depth of foundation below the ground level.

2.3.4 Wet Cultivated

To be used for locations where there is no sub-soil water within the foundation depth but which are in surface water for long period with water penetration not exceeding one meter below the ground level e.g paddy fields/cultivated field. However, if water penetration due to surface water is more than one meter below ground level, the adoption of suitable foundation shall be decided in consultation with the Employer.



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2.3.5 Partially Submerged

To be used at locations where sub-soil water table is met between 0.75 meter and 1.5metre below the ground level.

2.3.6 Fully Submerged

To be used at locations where sub-soil water table is met at less than 0.75 meter below the ground level.

2.3.7 Black Cotton Soil

To be used at locations where soil is clayey type, not necessarily black in colour, which shrinks when dry and swells when wet, resulting in differential movement. For designing foundations, for such locations, the soil is considered submerged in nature.

2.3.8 Fissured - Rock

To be used at locations where decomposed or fissured rock, hard gravel, kankar, limestone, laterite, conglomerates or any other soil of similar nature is met. Under cut type foundation is to be used for fissured rock locations.

In case of fissured rock locations, where water table is met at 1.5M or more below ground level, wet fissured rock foundations shall be adopted. Where fissured rock is encountered with subsoil water table less than 1.5 meter below ground level, submerged fissured rock foundations shall be adopted. In case of dry locations dry fissured rock foundations shall be adopted.

2.3.9 Hard Rock

The locations where chiseling, drilling and blasting is required for excavation for monolithic rock for a particular leg/tower, Hard rock type foundations are to be used. For these locations rock anchoring is to be provided to resist uplift forces.

For quoting prices of Hard Rock foundations, Rock level shall be assumed at

1.5 meters below the ground level. Due to change in Rock level, no extra payment shall be payable on account of increase in concrete volume, excavation volume and weight of reinforcement, also no recovery shall be made if the actual volume of concrete, excavation and weight of reinforcement are less than that quoted in Schedule of prices. However, for design purpose, Rock level shall be considered at ground level and no over burden soil weight shall be considered for resisting the uplift.

2.3.10 The sub-soil water table is not constant and its level changes during different

seasons due to various factors. In case during soil investigation/trial pit or during excavation, if wet soil / fissures rock is encountered within the foundation depth, it is to be considered that water table has been



35

encountered (considering that water table had reached that level sometime in past) and accordingly type of foundation shall be classified.

2.3.11 Where soil is of composite in nature, classification of foundation shall be

according to the type of soil predominant in the foundation pit. 2.3.12 The foundation classification at any particular location shall be based on the

type of soil (clay / sandy / silt / fissured rock etc) and water table, presence of surface water, etc. at the location. However, in case of locations which are in vicinity of rivers, depending upon case to case, type of foundation is to be decided considering other aspects also e.g in case RL (reduced level) of a location in comparison to the HFL is lower and there is possibility of submergence at the time of floods due to absence of river bunds / protection etc., FS type foundation with suitable raised chimney is to be adopted. Further in case there is a possibility of change in river course, considering the nature and turbulence of probable water flow and subsequent scouring of soil, pile type or special foundation may be considered for these locations.

2.3.13 In addition to above, if required, depending on the site conditions special

type foundations shall also be provided by the contractor suitable for intermediate conditions under the above classifications to effect more economy for following reasons:

(a) Shallow Depth or Raised Chimney foundations are necessarily required to

suit the site condition or (b) Soil properties as per the soil report at particular location are found

inferior than that considered in design. However, in case, soil properties as per soil report are found superior than that considered in design, no change in foundation design / price shall be applicable.

2.3.14 The proposal for special foundations shall be submitted by the Contractor

based on the detailed soil investigation report / to suit site conditions and approval for the same shall be obtained from the Employer. Decision of the Employer shall be final and binding with respect to requirement of special foundation. Payment for special foundation shall be made as explained in clause 6.3.2 of this section

2.4 Type of Foundations

The Bidder shall offer open type of foundation (i.e. slab and chimney) with maximum depth of foundation as 3.0 meters for above classification of foundations depending on economy and feasibility of construction at site.

Bidder has to furnish along with the bid one sample calculation for each type of foundation required as per BPS for verification of correctness of design procedure adopted by the Bidder.



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2.5 Soil Investigation

The contractor shall undertake soil investigation as per clause 4.0 of Section-3 at tower locations as approved by the Employer. The provisional number of soil testing locations is furnished in Schedule of Prices. Unit rates for the same are to be furnished by the bidder in appropriate Schedules of Price, for adjustment purpose with actual quantities required for soil testing.

2.6 Design of Foundations

2.6.1 Loads on Foundations

2.6.1.1 The foundations shall be designed to withstand the specific loads of the superstructure and for the full footing reactions obtained from the structural stress analysis in conformity with the relevant factors of safety.

2.6.1.2 The reactions on the footings shall be composed of the following type of loads for which these shall be required to be checked:

a) Max. Tension or uplift along the leg slope.

b) Max. Compression or down-thrust along the leg slope.

c) Max. Horizontal shear or side thrust.

2.6.1.3 Overload Factor for Foundation Loads:

The overload factor for foundation loads shall be considered as 1.1 i.e. the reaction on the foundations shall be increased by 10 percent.

2.6.2 Stability Analysis

2.6.2.1 In addition to the strength design, stability analysis of the foundation shall be done to check the possibility of failure by over-turning, uprooting, sliding and tilting of the foundation.

2.6.2.2 The following primary types of soil resistance shall be assumed to act in resisting the loads imposed on the footing in earth:

A) Resistance Against Uplift

The uplift loads will be assumed to be resisted by the weight of earth in an inverted frustum of a conical pyramid of earth as per formula detailed in Annexure –A of this Section on the footing pad whose sides make an angle equal to the angle of repose of the earth with the vertical, in average soil. The weight of concrete embedded in earth and that above the ground will also be considered for resisting the uplift. In case where the frustum of earth pyramids of two adjoining legs super-imposed each other, the earth frustum will be assumed truncated by a vertical plane passing through the centre line of the tower base.



37

B) Resistance Against Down Thrust

The down-thrust loads combined with the additional weight of concrete above earth will be resisted by bearing strength of the soil assumed to be acting on the total area of the bottom of the footings.

C) Resistance Against Side-Thrust

The lateral load capacity of a chimney foundation shall be based on chimney acting as a cantilever aided by passive earth resistance developed 500 mm below the ground level.

The chimney shaft shall be reinforced for the combined action of axial force, tension and compression and the associated maximum bending moment. In these calculations, the tensile strength of concrete shall be ignored.

The increase in vertical toe pressure due to maximum bending moment at the bottom of the slab shall be taken into account and the base itself shall be designed for structural adequacy. In this case, the allowable vertical toe pressure may be increased by 25%. The unit weight of reinforced concrete is stipulated in Table 2-2.

2.7 Design Criteria

2.7.1 As per IS: 456-2002 Partial safety factor shall be considered 1.5 for concrete and 1.15 for steel.

2.7.2 The overload factors for open type foundations shall be as 1.1 i.e. all the reactions (compression, tension and side thrust) on foundations shall be increased by 10 percent for development of foundation design.

2.7.3 The physical properties of soil under various conditions are furnished in TABLE 2.1 to be considered for the design of foundations. These type of foundations correspond to list of foundations furnished in Schedule of prices VOL III.

2.7.4 The composite rates quoted in Schedule of prices shall be payable for foundations developed based on above soil properties and classified as clause 4.2 of this Technical Specification. The composite rate shall be paid to the contractor for above foundations irrespective of change in approved design volumes in comparison to estimated Volumes. No extra payment shall be payable on account of increase in concrete volume, excavation volume, and at the same time no recovery shall be made from the composite foundation rates when the approved foundation volumes are less than quoted volumes. Further, once the foundations are classified based on the preponderant soil, the payment shall be made based on composite rate and extra claim is not admissible for excavation in different kinds of soil encountered inside the pit.

However, it may be noted that the soil properties furnished in TABLE 2.11 are tentative in nature. After soil investigations, if it is found that the foundations



38

listed in Schedule of Prices Vol. III cannot be used at that location; new foundation design shall be developed by the Contractor based on properties furnished in soil report. The payment for these foundations shall be made based on unit rate quoted for excavation, concreting and reinforcement.

2.7.5 Particulars of the foundations, along with the estimated volumes of concrete weight of reinforcing bars and excavation volumes for the various types of towers shall be given in the bid. The foundation shall be designed such as to satisfy the following conditions:

2.7.6 The thickness of concrete in the chimney portion of the tower footing would be such that it provides minimum cover of not less than100 mm from any part of the stub angle to the nearest outer surface of the concrete in respect of all dry locations limiting the minimum section of chimney to 300 mm square .In respect of all wet location, the chimney should have all around clearance of 150 mm from any part of stub angle limiting to 450 mm square minimum.

2.7.7 The chimney top or muffing must be at least 225 mm above ground level and also the coping shall be extended up to lower most joint level between the bottom lattices and the main corner legs of the tower. .

2.7.8 The centroidal axis of slab shall coincide with the axis of the chimney and pass through the center of foundation base. The design of the foundation(base slab and its reinforcement) shall take into account the additional stresses in the foundation resulting from the eccentricity introduced due to non-compliances of this requirement.

2.7.9 At least 100 mm thick pad of size equal to the base of slab with its sides vertical will be provided below the slab for R.C.C. type foundations.

2.7.10 In case of reinforced concrete slab, the slab thickness should not be less than 300 mm.

2.7.11 The minimum distance between the lowest edge of the stub angle and the bottom surface of concrete footing shall not be less than 100 mm or more than 150 mm in case of dry locations and not less than 150 mm or more than 200 mm in case of wet locations.

2.7.12 The total depth of open type foundations below the ground level shall not be less than 1.5 meters and more than 3 meters. To maintain the interchangeability of stubs for all types of foundations, for each type of tower, almost the same depths of foundations shall be used for different types of foundations.

2.7.13 The portion of the stub in the slab shall be designed to take full down-thrust or uplift loads by the cleats combined with the bond between stub angles and slab concrete. The Contractor shall furnish the calculation for uprooting of stub along with the foundation design. Bolted cleat angles evenly spaced in sets of 4



39

along all sides of embedded portion of the stub shall be provided to act as shear connector with sufficient number of bolts.

2.7.14 In case of R.C.C. foundations are having steel reinforcement in base slab, at least 50 mm. thick pad of lean concrete corresponding to 1:3:6 nominal mixes shall be provided to avoid the possibility of reinforcement rod being exposed due to unevenness of the bottom of the excavated pit.

2.7.15 The base slab of the foundation shall be designed for additional moments developing due to eccentricity of the loads.

2.7.16 The additional weight of concrete in the footing below ground level over the earth weight and the full weight of concrete above the ground level in the footing and embededded steel parts will also be taken into account adding to the down thrust.

TABLE 2.1

PROPERTIES OF SOIL ULTIMATE BEARING ANGLE OF REPOSE CAPACITY DEGREE KN/m2(Kg/m2)

1. For Normal Soil (a) Normal Dry Soil 268 (27350) 25 (b) Wet Soil Due to Presence 134 (13675) 15 of Subsoil/Surface Water (c ) Wet Black Cotton 134 (13675) 0 2. WEIGHT OF EARTH for Normal soil UNIT VALUE

(a) Dry KN/M3 (Kg/M3) 14.12 (1440)

(b) In presence of Surface Water KN/M3 (Kg/M3) 14.12 (1440)

(c) In presence of Subsoil Water KN/M3 (Kg/M3) 9.22 (940)

3. FISSURED ROCK

(a) Ultimate Bearing Capacity (both KN/M2 (Kg/M2) 498 (50800)

for Dry & Wet Fissured Rock)

(b) WEIGHT OF FISSURED ROCK

i) Dry KN/M3 ( Kg/M3) 14.12 (1440)



40

ii) In presence of Subsoil Water KN/M3 ( Kg/M3) 9.22 ( 940)

(c) ANGLE OF REPOSE

i) Fissured Rock in Dry Portion Degrees 20

ii) Fissured Rock in Presence of Water Degrees 10

4. HARD ROCK

a) Ultimate Bearing Capacity KN/M2 (Kg/M2) 1225.83 (125000)

b) Ultmate Bond between steel (Kg/CM2) 19.2

5. SANDY SOIL

(a) Ultimate Bearing Capacity (Kg/M2) (25000)

(b) WEIGHT KN/M3 (Kg/M3) 14.12 (1440)

(c) ANGLE OF REPOSE Degrees 20

The above soil properties of the earth will be measured by the Contractor at the various locations in conformity with the standard method of testing and the foundation design will be revised suiting the site conditions from such tests.

2.8 Properties of Concrete

The cement concrete used for the foundations shall generally be of grade M-20 having 1:1.5:3 nominal volumetric mix ratio with 20mm coarse aggregate for chimney portion and 20mm/40mm aggregates for pyramid or slab portion. All the properties of concrete regarding its strength under compression, tension, shear, punching and bending etc. as well as workmanship will conform to IS:456.

2.8.1 The weight of concrete to be considered for design of foundations is given in TABLE 2.2.

TABLE 2.2

WEIGHT OF CONCRETE .

TYPE OF WEIGHT OF DRY REGION WEIGHT IN PRESENCE CONCRETE KN / M3(Kg/m3) OF SUB-SOIL WATER KN / M3(Kg/m3)

Plain Concrete 21.96 (2240) 12.16 (1240)



41

Reinforced Concrete 23.54 (2400) 13.73 (1400)

2.8.2 The Quantity of minimum cement to be used per unit quantity of consumption for different mix (nominal mix) of concrete should be as follows:

Sl.no. Description Unit Quantity of Minimum cement to be used perUnit quantity of work (in kgs)

1. 1:1.5:3 nominal mix concrete Cu.m. 400

2. 1:2:4 nominal mix concrete Cu.m. 320

3. 1:3:6 nominal mix concrete Cu.m. 220

4. Random Rubble Masonry Cu.m. 83 with 1:6 cement mortar

In this regard utilisation record is to be maintained at site.

2.8.3 Alternatively, Ready Mix concrete from batching plant as per IS 4925 can also be used used with no extra payment and without any recovery. However Cement content shall be as per IS 456. The ready mix concrete shall conform to IS:4926. The selection and use of Materials for the ready mix concrete shall be in accordance with IS:456. The concrete shall be of M20 grade design mix as per IS:456. The transport of concrete and transportation time shall be as per IS:4926.

2.8.4 a) Cement used shall be ordinary Portland Cement, unless mentioned otherwise, conforming to the latest Indian Standard Code IS:269 or IS:8112 or IS:12269.

b) The Contractor shall submit the manufacturer’s certificate, for each consignment of cement procured, to the Employer. However Employer reserves the right to direct the Contractor to conduct tests for each batch/lot of cement used by the Contractor and Contractor will conduct those tests free of cost at the laboratory so directed by the Employer. The Contractor shall also have no claim towards suspension of work due to time taken in conducting tests in the laboratory. Changing of brand or type of cement within the same structure shall not be permitted without the prior approval of the Employer. Sulphate Resistant Cement shall be used if sulphate content is more than the limits specified in IS: 456, as per Geotechnical investigation report.

The curing time of cement will be decided at the time of execution of the work under the contract based on the certificate from a reputed laboratory which will be obtained and submitted by the Contractor.

2.8.5 Concrete aggregates shall conform to IS: 383-1970.



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2.8.6 The water used for mixing concrete shall be fresh, clean and free from oil, acids and alkalies, organic materials or other deleterious substances. Potable water is generally preferred.

2.8.7 Reinforcement shall conform to IS: 432-1966 for M.S bars and hard drawn steel wires and to IS: 1138-1966 and IS: 1786-1966 for deformed and cold twisted bars respectively. All reinforcement shall be clean and free from loose mill scales, dust, loose rust, and coats of paint, oil or other coatings, which may destroy or reduce bond. Contractor shall supply, fabricate and place reinforcement to shapes and dimensions as indicated or as required to carry out intent of drawings and specifications.

2.9 Measurement ,Unit Rates and Payment for Foundation

2.9.1 Measurement

2.9.1.1 The indicative shape of foundations is enclosed in this Specification. The bidder is required to quote the unit rates for different foundation types for a particular tower in the relevant Price Schedule.

2.9.1.2 The Bidder has to provide in the Bid the guaranteed foundation quantities (i.e. Excavation volume, Concrete volumes and Weight of Reinforcements) and unit rates for excavation, concreting and reinforcement for each type of foundation (as classified in clause 2.2 of this section) for each type of tower. Composite price quoted (as described in clause 3.4 of this section) in respective Schedule for each type of foundation must comply with unit rate quoted and guaranteed foundation quantities mentioned.

2.9.1.3 The concrete volume and dimensions of the foundation shall be determined from the drawing approved. Measurement of concrete volume shall be in cubic meters and shall be worked out to the second place of decimal

2.9.14 The excavation volumes for each tower footing shall be estimated assuming the faces of surrounding earth as vertical keeping a distance of 150 mm clearances from the extreme edge of the base slab of footing. For footings with undercut, excavation volumes shall be calculated as per drawings without any side clearance.

2.9.1.5 The steel required for reinforcement of foundation shall be provided by the Contractor. Measurement will be based on the calculated weights of actually used in tonnes corrected to third place of decimal, no allowance being made for wastage. No payments will be made for wire required for binding the reinforcement, chairs, bolsters and spacers, as the cost of these is deemed to be included in the unit rate quoted for the item of reinforcement.

2.9.2 UNIT RATE

2.9.2.1. The unit rates of excavation for each type of soil shall include excavation along with all associated activities like shoring, shuttering, dewatering till completion of foundation work stock piling, dressing, back filling of



43

foundations after concreting with excavated/borrowed earth (irrespective of lead) and consolidation of earth, carriage of surplus earth to the suitable point of disposal as required by the Employer or any other activity related to completion foundation work in all respect.

2.9.2.2 Form boxes shall be used for casting of foundations. The unit rate of concreting shall include the cost of supply, fabrication and placement of form boxes, cement, water, coarse and fine aggregates mixing and placing of concrete, curing of concrete and any other activities related to completion of concreting works of foundation.

2.9.2.3 The unit rate of ‘Reinforcement Steel’ shall include supply and placement of reinforcement steel, stirrups, wire for binding the reinforcement, chairs, bolsters and spacers etc. as required to complete the foundation work.

2.9.3 Payment for Foundation

2.9.3.1 Normal Foundations

Payment of normal foundations classified under clause 4.2 of this section shall be made as described in clause 5.4 of this section. The rate of foundation per tower shall include transportation of construction materials to the Site, excavation, concreting, reinforcement, shoring, shuttering, dewatering, stock piling, dressing, curing, backfilling the foundation after concreting with excavated / borrowed earth (irrespective of leads), consolidation of earth and carriage of surplus earth to the suitable point of disposal as required by the Employer or any other activities related to completion of foundation works.

2.9.3.2 Special Foundations

Unit rates for the payment purpose for special foundations (excavation, concreting and reinforcement) shall be based on the unit rates quoted by the Bidder as per Clause 6.1.2 for the same soil type.

2.9.3.2.1 Excavation

The measurement for this item shall be made on the basis of design excavation volume arrived at considering dimension of pit leaving 150mm gap around (except for under cut foundations) the base pad or actually excavated whichever is less and the unit rate of this item as indicated in Contract. The payment for excavation shall be made as per actual type of soil encountered at the time of excavation, but the total payment for excavation portion shall not exceed the amount as payable for excavation considering the soil type same as that of foundation classification. The decision of the Employer shall be final and binding with respect to classification of soil and foundations. In case unit rates for the same soil type under different tower types are different then the lowest rate among them shall be used for the payment purpose.



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2.9.3.2.2 Concrete

The payment for this item shall be made as per the actual volumes of concreting but limited to design volume based on unit rates for these items indicated in Contract.

2.9.3.2.3 Reinforcement

The measurement of reinforcement steel for payments shall be made based on the calculated weight of reinforcement steel as per relevant Indian Standard actually used in tones corrected to third place of decimal as calculated weight of steel as per design / working drawing whichever is less. No allowance will be made for wastage and others as per Clause 6.1.5.

2.10 CONSTRUCTION OF TOWER FOUNDATION

2.10.1 TESTING OF SOIL

2.10.1.1 The Contractor shall be required to undertake testing of soil for the tower locations in the manner specified under Clause 4.0 of section-3 of this Specification and shall submit his report about the subsoil water table, type of soil encountered, bearing capacity of soil, possibility of submergence and other soil properties required for the design of foundations. The Contractor shall also furnish soil resistivity values to the Employer along the line alignment.

2.10.2 Excavation

2.10.2.1 The excavation work for foundations shall be taken up by the Contractor after obtaining approval from Employer for the proposed stretch wise / section wise tower schedule, profile etc. prepared during Check / Detailed survey along the approved route alignment.

2.10.2.2 Except as specifically otherwise provided, all excavation for footings shall be made to the lines and grades of the foundations. The excavation wall shall be vertical and the pit dimensions shall be based on an assumed clearance of 150mm on all sides of the foundation pad. For footings with undercut, care shall be taken to carry out excavation as per drawings without any side clearance. All excavation shall be protected so as to maintain a clean sub grade and provide worker safety until the footing is placed, using timbering, shoring, shuttering, dewatering etc. as approved by the Employer. Contractor shall especially avoid disturbing the bearing surface of the pad. Any sand, mud, silt or other undesirable materials which may accumulate in the excavated pit or borehole shall be removed by Contractor before placing concrete.

2.10.2.3 The soil to be excavated for tower foundations shall be classified as follows depending upon the physical state of the soil at the time of excavation irrespective of the type of foundation installed:



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a) Dry Soil

Soil removable either manually, means of a spade and shovel or mechanically by proclains, excavator etc. Excavation done in dry soil for wet and fully submerged type of foundations shall also be covered under this.

b) Wet Soil

Where the subsoil water table is encountered within the range of foundation depth or land where pumping or bailing out of water is required due to presence of surface water shall be treated as wet soil. The excavation done in wet soil in case of wet and fully submerged type of foundation shall also be covered under this.

c) Dry Fissured Rock

Limestone, laterite, hard conglomerate or other soft or fissured rock in dry condition which can be quarried or split with crowbars, wedges, pickaxes or by mechanical shovels etc. However, if required, light blasting may be resorted to for loosening the material but this will not in any way entitle the material to be classified as hard rock.

d) Wet Fissured Rock

Above fissured rock, when encountered with subsoil water within the range of foundation depth or land where pumping or bailing out of water is required, shall be treated as wet fissured rock.

e) Hard Rock

Any rock excavation, other than specified under fissured rock above, for which blasting, drilling, chiseling are required. The unit rate quoted for hard rock excavation shall be inclusive of all costs for such drilling (including drilling required for anchoring), chiseling and blasting, etc.

2.10.2.4 However, where soil is of composite in nature, classification of foundation shall be according to the type of soil predominant in the footing and payment shall be made accordingly.

2.10.2.5 No extra payment shall be admitted for the removal of fallen earth into a pit or borehole once excavated. Shoring and timbering / shuttering as approved by authorized representative of the Employer shall be provided by the Contractor when the soil condition is so bad that there is likelihood of accident due to the falling of earth.

2.10.2.6 Where rock is encountered, the holes for tower footings shall preferably be drilled. Blasting where resorted to as an economy measure, if permitted by the Employer shall be done with utmost care to minimize fracturing of rock and using extra concrete for filling the blasted area. All necessary



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precautions for handling and use of blasting materials shall be taken. In cases where unnecessarily large quantities are excavated / blasted, resulting in placement of large volumes of concrete, payment of concrete shall be limited to design volumes of excavation, concreting, reinforcement etc. In case where drilling is done, the stubs may be shortened suitably with the approval of the Employer or his authorized representatives.

2.10.2.7 The Contractor shall arrange & supply requisite blasting material, and be responsible for its storage and use, without any extra cost to the Purchaser.

2.10.3 Setting of Stubs

2.10.3.1 For all towers the Contractor shall submit for approval the proposed method for setting of stubs.

2.10.3.2 The stubs shall be set correctly and precisely in accordance with approved method at the exact location, alignment and levels with the help of stub setting templates and leveling instruments. Stubs setting shall be done in the presence of Employer’s representative available at site where required and for which adequate advance intimation shall be given to Employer by Contractor. Tolerances as per provisions of IS: 5613 shall be allowed for stub setting.

2.10.3.3 Setting of stub at each location shall be approved by Employer.

2.10.3.4 However, in hilly region for towers with unequal leg extensions props may be used with complete accuracy and high skilled supervision, subject to prior approval from Employer.

2.10.3.5 As per the schedule testing of all four towers must be completed before the start of casting foundations. However, for any reason if the testing of tower gets delayed Contractor shall not hold the casting of foundation work and shall cast the foundations with the stub of untested tower as per the design at his own risk and cast. Accordingly Contractor shall keep enough safety while choosing the section for the stub /leg of last panel of tower to ensure that that the section for stub / leg of last panel shall not change during completion of tower testing.

2.10.4 Stub Setting Templates / Props

2.10.4.1 Stub setting templates shall be designed and arranged by the Contractor at his own cost for all types of towers with or without body extension. Stub templates for standard towers and towers with body extension upto 9 M shall be of adjustable type. The Contractor shall also arrange for props for setting of stubs at specific locations where use of prop is approved by the Employer. Stub templates / props should be painted.

2.10.4.2 The Contractor shall deploy sufficient number of templates / props (where ever required) for timely completion of the line without any extra cost to Employer.



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2.10.4.3 One set of each type of stub setting template / props (if used) shall be supplied to the Employer, on completion of the project, at no extra cost to Employer.

2.10.4.4 Generally for a transmission line following number of stub setting templates shall be deployed by the Contractor:

Templates for tower type Nos. to be deployed

DA 3

For each type of DB, DC 6 for DB and 3 Each for others and DD type

However, if Employer feels that more templates are required for timely completion of the lines, the Contractor shall have to deploy the same without any extra cost to Employer.

The number of sets of prop (if permitted) to be supplied, will depend as per actual site condition and completion schedule of line.

2.10.5 Mixing, Placing and Compacting of Concrete

2.10.5.1 The concrete shall be mixed in the mechanical mixer. However, in case of difficult terrain, hand mixing may be permitted at the discretion of the Employer. The water for mixing concrete shall be fresh, clean and free from oil, acids and alkalis. salty or blackish water shall not be used.

Alternatively, Ready Mix concrete from batching plant as per IS 4925 can also be used used with no extra payment and without any recovery. However Cement content shall be as per IS 456. The ready mix concrete shall conform to IS:4926. The selection and use of Materials for the ready mix concrete shall be in accordance with IS:456. The concrete shall be of M20 grade design mix as per IS:456. The transport of concrete and transportation time shall be as per IS:4926.

2.10.5.2 Mixing shall be continued until there is uniform distribution of material and mix is uniform in colour and consistency, but in no case the mixing be carried out for less than two minutes. Normal mixing shall be done close to the foundation but exceptionally, in difficult terrain, the concrete may be mixed at the nearest convenient place. The concrete shall be transported from the place of mixing to the place of final deposit as rapidly as practicable by methods which shall prevent the segregation or loss of any ingredient. The concrete shall be placed and compacted before setting commences.

2.10.5.3 To avoid the possibility of reinforcement rods being exposed due to unevenness of the bottom of the excavated pit, a pad of lean concrete 50mm thick and corresponding to a 1:3:6 nominal mix shall be provided at the bottom of the pad.



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2.10.5.4 Form boxes shall be used for casting all types of foundations except at an undercut interface for which the adjoining subsurface material shall provide adequate support.

2.10.5.5 The concrete shall be laid down in 150mm layers and consolidated well, so that the cement cream works, up to the top and no honey-combing occurs in the concrete. A mechanical vibrator shall be employed for compaction of the concrete. However, in case of difficult terrain, manual compaction may be permitted at the discretion of the Employer. Monolithic casting of foundations must be carried out. However, in case of unavoidable circumstances, a key construction joint can be provided at the chimney-pad interface subject to approval of the Employer. However nothing extra shall be paid to the Contractor for providing such construction joints. After concreting the chimney portion to the required height, the top surface should be finished smooth with a slight slope towards the outer edge for draining rain water.

2.10.5.6 Wet locations shall be kept completely dewatered, both during and 24 hours after placing the concrete, without disturbance of the concrete.

2.10.5.7 If minor defects in concrete surface is found after the form work is removed, the damage shall be repaired with a rich cement sand mortar to the satisfaction of the Employer before the foundation is back filled.

2.10.6 Curing

The concrete shall be cured by maintaining the concrete wet continuously for a period of at least 10 days after placing. Once the concrete has set for 24 hours the pit may be backfilled with selected moistened soil and well consolidated in layers not exceeding 200mm thickness and thereafter both the backfill earth and exposed chimney shall be kept wet for the remainder of the prescribed 10 days. The exposed concrete chimney shall also be kept wet by wrapping empty gunny bags around it and wetting the bags continuously during the critical 10 days period.

2.10.7 Backfilling and Removal of Stub Templates

2.10.7.1 After opening of formwork and removal of shoring, timbering, etc., backfilling shall be started after repairs, if any, to the foundation concrete. Backfilling shall normally be done with the excavated soil, unless it is a clay type or it consists of large boulders/stones, in which case the boulders shall be broken to a maximum size of 80-mm. At locations where borrowed earth is required for backfilling, Contractor shall bear the cost irrespective of leads & lift.

2.10.7.2 The backfilling materials shall be clean and free from organic or other foreign materials. A clay type soil with a grain size distribution of 50% or more passing the number 200 sieve as well as a black cotton soil is unacceptable for backfilling. The earth shall be deposited in maximum 200mm layers, leveled, wetted if necessary and compacted properly before another layer is deposited. The moisture content for compaction shall be based on the Proctor compaction test results given in the Geo-technical Report, Clause 3.0



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of section 3. The density of the compacted backfill material may further be verified to the satisfaction of the Employer based on the sand-cone method described in the ASTM D1556-82 standard.

2.10.7.3 The backfilling and grading shall be carried to an elevation of about 75mm above the finished ground level to drain out water. After backfilling 50mm high, earthen embankment (Bandh) will be made along the sides of excavation pits and sufficient water will be poured in the backfilling earth for at least 24 hours. After the pits have been backfilled to full depth the stub template can be removed.

2.10.8 Benching

When the line passes through hilly / undulated terrain, leveling the ground may be required for casting of tower footings. All such activities shall be termed benching and shall include cutting of excess earth and removing the same to a suitable point of disposal as required by Employer. Benching shall be resorted to only after approval from Employer. Volume of the earth to be cut shall be measured before cutting and approved by Employer for payment purposes. Further, to minimize benching, unequal leg extensions shall be considered and provided if found economical. If the levels of the pit centers be in sharp contrast with the level of tower centre, suitable leg extensions may be deployed as required. The proposal shall be submitted by the Contractor with detailed justification to the Employer.

2.10.9 Protection of Tower and Tower Footing

2.10.9.1 Tower shall be spotted such that the quantity of revetment is optimum. For tower locations in undulated terrain such as hill / mountain slopes, options like use of unequal leg extensions for towers, unequal chimney extensions etc. shall be explored by the contractor for optimizing the need for revetment & benching.

2.10.9.2 The work shall include all necessary stone revetments, concreting and earth filling above ground level, the clearing from site of all surplus excavated soil, special measures for protection of foundation close to or in small water streams (Nalas), river bank / bed, undulated terrain, protection of up hill / down hill slopes required for protection of tower etc., including suitable revetment or galvanised wire netting and meshing packed with boulders. The top cover of stone revetment shall be sealed with M-15 concrete (1:2:4 mix). Contractor shall recommend protection at such locations wherever required. Details of protection of tower/tower footing are given in drawing enclosed with these specifications for reference purpose only.

2.10.9.3 In protection of tower footings works the backfilling shall generally be done using soil excavated at site unless deemed unsuitable for backfilling. In the latter case, backfilling shall be done with borrowed earth of suitable quality irrespective of leads and lift. The unit rate for backfilling quoted in Price Schedules shall include the required lead and consolidation and leveling of earth after backfilling.



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2.10.9.4 The provisional quantities for protection work of foundations are furnished in Price Schedule of Bid. The unit rates shall also be applicable for adjusting the actual quantities of protection works done. These unit rates shall hold good for protection work carried out on down hills or up hills slopes applicable for the tower locations.

2.10.9.5 The unit rates for random rubble masonry revetment quoted in price schedule shall also include excavation & (1:5) random masonry and unit rate for top sealing with M-15 concrete. For payment purposes the volume of random rubble masonry revetment shall be measured from bottom to top sealing coat and paid at the quoted rates indicated in price schedule.

No extra rates shall be paid for allied work such as excavation, for revetment, packed stone at head of weep holes etc. However, no deduction shall be made for the volume enclosed by weep holes. The locations where both benching and protection of tower footing are envisaged, an economy got to be established against providing unequal leg extension.

2.10.9.6 For some of the locations in small water streams (Nalas), river bed or undulated terrain etc., boulders of minimum. 150mm size bounded and packed in galvanised wire net / mesh of 8 SWG wire and 152 square (maximum.) mesh are to be provided. These stones shall be provided in crates size of 2.0mx2.0m or as deemed suitable for a particular location. Measurement shall be taken in cubic meters and 15% deduction will be made for void from cage / stack measurements.

3.0 Tower Erection, Stringing and Installation of Line Materials

3.1 General

3.1.1 The scope of erection work shall include the cost of all labour, tools and plant such as tension stringing equipment and all other incidental expenses in connection with erection and stringing work. The bidders shall indicate in the offer the sets of stringing equipment he would deploy exclusively for this transmission line package. The stringing equipment shall be of sufficient capacity to string simultaneously a bundle of TWIN BISON Conductors.

3.1.2 The Contractor shall be responsible for transportation to site of all the materials to be provided by the Contractor as per the scope of work to site, proper storage and preservation at his own cost, till such time the erected line is taken over by the Employer.

3.1.3 Contractor shall set up required number of stores along the line and the exact location of such stores shall be discussed and agreed upon with the Employer. Purchaser supplied items shall be dispatched to nearest store set up by the Contractor. At the store receipt, unloading and further transportation to the site shall be the entire responsibility of the Contractor.

3.1.4 Payment for stringing shall be done on the basis of per kilometer of line route length (conductor: comprising of three (3) phases with two (2) conductors per phase and earth wire: comprising of one (1) wire) and irrespective of number



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of tension/ suspension towers. The units of measurement for erection of tower and its body extensions, installation of tower earthing and tower accessories, installation of insulators, hardware fittings and conductor & earth wire accessories are indicated in the relevant Price Schedules

3.2 Treatment of Minor Damage in Galvanisation

Minor defects in hot-dip galvanised members shall be repaired by applying zinc rich primer and two coats of enamel paint to the satisfaction of the Employer before erection.

3.3 Assembly of Tower

The Contractor shall give complete details of the erection procedures he proposes to follow.

3.3.1 The method for the erection of towers shall ensure the following:

a) Straining of the members shall not be permitted for positioning. It may, however, be necessary to match hole positions at joints using Tommy bars not more than 450 mm in length.

b) Prior to erection of an upper section, the lower sections shall be completely braced, and all bolts provided tightened adequately in accordance with approved drawings to prevent any mishap during tower erection.

c) All plan diagonals, oblique bracings etc for relevant section of tower shall be in place prior to assembly of an upper Section.

d) The bolt positions in assembled towers shall be as per IS: 5613 (Part II/Section 2).

e) Tower shall be fitted with number plates, danger plates, phase plates, Circuit Plates and anti-climbing device as described.

f) After complete erection of the tower, all blank holes, if any, are to be filled by bolts and nuts of correct size.

3.4 Tightening of Bolts and Nuts

3.4.1 All nuts shall be tightened properly using correct size spanner and torque wrench. Before tightening, it will be verified that filler washers and plates are placed in relevant gap between members, bolts of proper size and length are inserted, and one spring washer is inserted under each nut. In case of step bolts, spring washers shall be placed under the outer nuts. The tightening shall progressively be carried out from the top downwards, care being taken that all bolts at every level are tightened simultaneously. The threads of bolts projecting outside the nuts shall be punched at their position on the diameter to ensure that the nuts are not loosened in course of time. If, during tightening, a nut is found to be slipping or running over the bolt threads, the bolt together with the nut shall be replaced.



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3.4.2 The threads of all the bolts except for Anti-theft bolts, projected outside the nuts shall be welded at two diametrically opposite places, the circular length of each welding shall be at least 10 mm. The welding shall be provided from ground level to bottom cross arm for double circuit towers. However, for towers, with +18 meter, +25 meter extensions and river crossing towers, the welding shall be provided from ground level to 30m height from stub level. After welding zinc-rich primer having approximately 90% zinc content shall be applied to the welded portion. At least two coats of the paint shall be applied. The surface coated with zinc rich primer shall be further applied with two finish coats of high build enamel of the grade recommended by the manufacturer of the zinc rich primer. The cost of welding and paint including application of paint shall be deemed to be included in the erection price.

3.4.3 In addition to the tack welding of nuts with bolts, as described above, the Contractor can also propose some alternative arrangements, like use of epoxy resin adhesive which can serve the purpose of locking the nut permanently with the bolt and thus preventing pilferage of the tower members.

3.5 Insulator Hoisting

Suspension insulator strings shall be used on Suspension towers (DA) and double tension insulator strings on angle and dead end towers. These shall be fixed on all the towers just prior to the stringing. Damaged insulators and strings, if any, shall not be employed in the assemblies. Prior to hoisting, all insulators shall be cleaned in a manner that will not spoil, injure or scratch the surface of the insulator, but in no case shall any oil be used for that purpose. For checking the soundness of insulators, IR measurement using 5 kV (DC) Meger shall be carried out on 100% insulators. Corona control rings/arcing horn shall be fitted in an approved manner. The yoke arrangements be horizontal for tension string and vertical (parallel to transverse face of tower) for suspension strings. Torque wrench shall be used for fixing various line materials and components, such as suspension clamp for conductor and earth wire, etc., whenever recommended by the manufacturer of the same.

3.6 Handling of Conductor and Earth wire

3.6.1 Running Out of the Conductors

3.6.1.1 The conductors shall be run out of the drums from the top in order to avoid damage. The Contractor shall be entirely responsible for any damage to tower or conductors during stringing.

3.6.1.2 A suitable braking device shall be provided to avoid damaging, loose running out and kinking of the conductors. Care shall be taken that the conductors do not touch and rub against the ground or objects which could scratch or damage the strands.



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3.6.1.3 The sequence of running out shall be from the top to downwards i.e. the earth wire shall be run out first followed in succession by the conductors. Unbalanced loads on towers shall be avoided as far as possible.

3.6.1.4 The Contractor shall take adequate steps to prevent clashing of sub conductors until installation of the spacers/spacer dampers. Care shall be taken that sub conductors of a bundle are from the same Contractor and preferably from the same batch so that creep behavior of sub conductors remains identical. During sagging, care shall be taken to eliminate differential sag in sub-conductors as far as possible. However, in no case shall sag mismatch be more than 25mm.

3.6.1.5 Though towers shall be designed for one side stringing condition, towers shall be well guyed and all necessary steps shall be taken by the Contractor to avoid damage tower / conductor during stringing operations. Guying proposal along with necessary calculations shall be submitted by the Contractor to Employer for approval. All expenditure related to this work is deemed to be included in the Price quoted for stringing and no extra payment shall be made for the same.

3.6.1.6 When the line under construction runs parallel to existing energised power lines, the Contractor shall take adequate safety precautions to protect personnel; from the potentially dangerous voltage built up due to electromagnetic and electrostatic coupling in the pulling wire, conductors and earth wires during stringing operations.

3.6.1.7 The Contractor shall also take adequate safety precautions to protect personnel from potentially dangerous voltage build up due to distant electrical storms.

3.6.2 Running Blocks

3.6.2.1 The groove of the running blocks shall be of such a design that the seat is semicircular and larger than the diameter of the conductor / earth wire and it does not slip over or rub against the sides. The grooves shall be lined with hard rubber or neoprene to avoid damage to conductor and shall be mounted on properly lubricated bearings.

3.6.2.2 The running blocks shall be suspended in a manner to suit the design of the cross-arm. All running blocks, especially at the tensioning end will be fitted on the cross-arms with jute cloth wrapped over the steel work and under the slings to avoid damage to the slings as well as to the protective surface finish of the steel work.

3.6.3 Repairs to Conductors

3.6.3.1 The conductor shall be continuously observed for loose or broken strands or any other damage during the running out operations.

3.6.3.2 Repairs to conductor if necessary, shall be carried out with repair sleeve.



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3.6.3.3 Repairing of the conductor surface shall be carried out only in case of minor damage, scuff marks, etc. The final conductor surface shall be clean, smooth and free from projections, sharp points, cuts, abrasions, etc.

3.6.3.4 The Contractor shall be entirely responsible for any damage to the towers during stringing.

3.6.4 Crossings

Derricks or other equivalent methods ensuring that normal services need not be interrupted nor cause damage to property, shall be used during stringing operations where roads, channels, telecommunication lines and power lines have to be crossed. However, shut down shall be obtained when working at crossings of overhead power lines. The Contractor shall be entirely responsible for the proper handling of the conductor, earth wire and accessories in the field.

3.7 Stringing of Conductor and Earth wire

3.3.1 The stringing of the conductor for 220 kV line shall be done by the control tension method. The equipment shall be capable of maintaining a continuous tension per bundle such that the sag for each conductor is about twenty percent greater than the sags specified in the stringing sag table.

3.3.2 The bidder shall give complete details of the stringing methods he proposes to follow. Prior to stringing the Contractor shall submit the stringing charts for the conductor and earth wire showing the initial and final sags and tension for various temperatures and spans along with equivalent spans in the lines for the approval of the Employer.

3.3.3 A controlled stringing method suitable for simultaneous stringing of the sub conductors shall be used. The two conductors making one phase bundle shall be pulled in and paid out simultaneously. These conductors shall be of matched length. Conductors or earth wires shall not be allowed to hang in the stringing blocks for more than 96 hours before being pulled to the specified sag.

3.3.4 Conductor creep are to be compensated by over tensioning the conductor at a

temperature of 260C lower than the ambient temperature or by using the initial sag and tensions indicated in the tables.

3.8 Jointing

3.8.1 When approaching the end of a drum length at least three coils shall be left in place when the stringing operations are stopped. These coils are to be removed carefully, and if another length is required to be run out, a joint shall be made as per the recommendations of the accessories manufacturer.

3.8.2 Conductor splices shall not crack or otherwise be susceptible to damage in the stringing operation. The Contractor shall use only such equipment / methods during conductor stringing which ensures complete compliance in this regard.



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3.8.3 All the joints on the conductor and earth wire shall be of the compression type, in accordance with the recommendations of the manufacturer, for which all necessary tools and equipment like compressors, dies etc., shall be obtained by the Contractor. Each part of the joint shall be cleaned by wire brush till it is free of dust or dirt etc. and be properly greased with anti-corrosive compound, If required and as recommended by the manufacturer, before the final compression is carried out with the compressors.

3.8.4 All the joints of splices shall be made at least 30 meters away from the tower structures. No joints or splices shall be made in spans crossing over main roads and small rivers with tension spans. Not more than one joint per sub conductor per span shall be allowed. The compression type fittings shall be of the self centering type or care shall be taken to mark the conductors to indicate when the fitting is centered properly. During compression or splicing operation, the conductor shall be handled in such a manner as to prevent lateral or vertical bearing against the dies. After compressing the joint the aluminium sleeve shall have all corners rounded, burrs and sharp edges removed and smoothened.

3.8.5 During stringing of conductor to avoid any damage to the joint, the Contractor shall use a suitable protector for mid span compression joints in case they are to be passed over pulley blocks / aerial rollers. The pulley groove size shall be such that the joint along with protection can be passed over it smoothly.

3.9 Tensioning and Sagging Operations

3.9.1 Tensioning and Sagging operations shall be done in accordance with the `approved stringing charts or sag tables before conductors and earth wire are finally attached to the towers through insulator strings and earth wire clamps respectively. The “initial” stringing chart shall be used for the conductor and final stringing chart for the earth wire. The conductors shall be pulled up to the desired sag and left in running blocks for at least one hour after which the sag shall be rechecked and adjusted, if necessary, before transferring the conductors from the running blocks to the suspension clamps. The conductor shall be clamped within 96 hours of sagging in.

3.9.2 Dynamometers shall be employed for measuring tension in the conductor and earthwire. Dynamometers employed shall be periodically checked and calibrated with the standard Dynamometer.

3.9.3 The sag will be checked in the first and the last section span for sections up to eight spans, and in one additional intermediate span for sections with more than eight spans. The sag shall also be checked when the conductors have been drawn up and transferred from running blocks to the insulator clamps.

3.9.4 The running blocks, when suspended from the transmission structure for sagging, shall be so adjusted that the conductors on running blocks will be at the same height as the suspension clamp to which it is to be secured.



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3.9.5 At sharp vertical angles, conductor and earth wire sags and tensions shall be checked for equality on both sides of the angle tower and running block. The suspension insulator assemblies will normally assume vertical position when the conductor is clamped.

3.9.6 Tensioning and sagging operations shall be carried out in calm weather when rapid changes in temperature are not likely to occur.

3.10 Clipping In

3.10.1 Clipping of the conductors into position shall be done in accordance with the manufacturer’s recommendations. Conductor shall be fitted with armor rods where it is made to pass through suspension clamps.

3.10.2 Jumpers at section and angle towers shall be formed to parabolic shape to ensure maximum clearance requirements. Pilot suspension insulator strings shall be used, if found necessary, to restrict jumper swing to design values.

3.10.3 Fasteners in all fittings and accessories shall be secured in position. The security clip shall be properly opened and sprung into position.

3.11 Fixing of Conductors and Earth wire Accessories

Conductor and earth wire accessories including Spacers (for bundle conductor) and Vibration Dampers shall be installed by the Contractor as per the design requirements and manufacturer’s instruction within 24 hours of the conductor / earthwire clamping. While installing the conductor and earth wire accessories, proper care shall be taken to ensure that the surfaces are clean and smooth and that no damage occurs to any part of the accessories or conductors. Torque wrench shall be used for fixing the Spacers, Vibration Dampers & Suspension Clamps etc. and torque recommended by the manufacturer of the same shall be applied.

3.12 Replacement

If any replacement is to be effected after stringing and tensioning or during maintenance, leg member and bracing shall not be removed without reducing the tension on the tower by proper guying techniques or releasing of the conductor. For replacement of cross arms, the conductor shall be suitably tied to the tower at tension points or transferred to suitable roller pulleys at suspension points.

3.13 Extra Consumption of Line materials

3.13.1 The quantity of conductor and earth wire to be incorporated in the line shall be worked as per the following norms.

Quantity of Conductor = Final Line Length as per Detailed/ Check survey x 3 phases x Nos. of conductor per bundle X No. of circuits

Quantity of Earth wire = Final Line Length as per Detailed/ Check survey x no. of ground wires to be strung.



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Quantity of OPGW = Final Line Length as per Detailed/ Check survey x no. of OPGW to be strung

3.13.2 Although extra consumption over and above the quantities incorporated in the works is not permitted, the Contractor shall make every effort to minimise breakage, losses and wastage of the line materials during erection.

3.13.3 The quantity of conductor and earth wire as described above shall also consider necessary sag, jumpering, damage, loss and wastage etc .

3.13.4 The Contractor shall not be required to return to the Employer empty conductor and earth wire drums and shall dispose off the same at his cost.

3.13.5 Any conductor and earth wire drum which has been opened by the Contractor shall not be taken back by Employer and the unused conductor or earth wire in such drums shall be treated as waste.

3.13.6 For calculation of conductor & earth wire consumption in hilly (mountainous) stretches inclined distance between towers shall be considered, instead of horizontal distance between them.

3.13.7 The quantities of line materials to be supplied by the contractor (i.e. Conductor, Earth wire, Hardware fittings & Accessories) as indicated in the bill of quantities are tentative and the actual quantity shall depend upon detailed survey/check survey. Contractor shall be responsible for regulating the supplies of contractor supplied materials in the basis of actual requirements. The Employer shall have right, not to take any surplus contractor supplied line materials.

3.13.8 OPGW shall be supplied as per per standard length of 5 kms in plain area and 3 kms in hilly area

3.14 Final checking, Testing and Commissioning

3.14.1 After completion of the works, final checking of the line shall be carried out by the Contractor to ensure that all foundation works, tower erection and stringing have been done strictly according to the specifications and as approved by the Employer. All the works shall be thoroughly inspected in order to ensure that :

a) Sufficient backfilled earth covers each foundation pit and is adequately compacted;

b) Concrete chimneys and their copings are in good condition and finely shaped.

c) All tower members are used strictly according to final approved drawing and are free from any defect or damage whatsoever.

d) All bolts are properly tightened, punched, tack welded and painted with zinc rich paint.



58

e) The stringing of the conductors and earth wire has been done as per the approved sag and tension charts and desired clearances are clearly available;

f) All conductor and earth wire accessories are properly installed;

g) All other requirements for completion of works such as fixing of danger plate, phase plate, number plate, anti-climbing device etc. have been fulfilled.

h) Wherever required, that proper revetment (erosion protection) is provided;

i) The original tracings of profile and route alignment as well as foundation design & working drawings, tower design, structural drawings, bill of material and shop drawings of all towers are submitted to the Employer for reference and record.

j) The insulation of the line as a whole is tested by the Contractor through provision of his own equipment, labour etc., to the satisfaction of the Employer.

k) All towers are properly grounded.

l) The line is tested satisfactorily for commissioning purpose.

m) The right of way along the route of line is clear of all obstructions and meets requirements of clause 5.3 of IS:5613 (Part-3, Section – 2)

n) Any defect found as a result of testing shall be rectified by the contractor forthwith to the satisfaction of the Employer without any extra charges.

o) Before taking over the line by the Employer, the line shall be energized at full specified voltage.

3.14.2 The contractor should also fulfill the requirements of pre-commissioning

4.0 Field Quality Plan

All field activity shall be carried out in accordance with Standard Field Quality plan as given in Appendix –II to this Specification.


STANDARDISED FIELD QUALITY PLAN

Page 1 of 23

S.

No.

Description of

Activity

Items to be Checked Tests/Checks to be done Ref. documents Check/Testing Counter Check/Test by

EMPLOYER

Accepting authority

of EMPLOYER Agency Extent

1. Preliminary

/Detailed

Survey

a) Route alignment Optimization of route

length

a. Preliminary survey.

b. Topographical map

c. Tower spotting data

given by Engg.

Contractor

100% at Field

100% based on record

documents

Project In-charge

b) Route profiling &

tower spotting.

1. Ground clearance.

2. Cold wt. Span

3. Hot wt. Span

4. Sum of Adj. Span

(wind span)

5. Angle of Devn.

6. Suitability of Tower

spotting in hilly area

a. Sag template

b. Tower Spotting data

c. Route alignment

Contractor

-do-

-do-

-do-

-do-

-do-

100% at Field

-do-

-do-

-do-

-do-

-do-

100% based on record

documents

-do-

-do-

-do-

Verification of 100% at Field

Site In-charge

2. Check Survey Tower Location & Final

Length

i) Alignment

ii) Final Length

iii) Angel of deviation &

pit marking-

a. Route alignment

b. Tower Schedule

c. Profile

Contractor

-do-

100% at Field

-do-

i) All angle towers in plains

and 50% in hilly terrains.

ii) Final length to be checked

on 100% basis based on

records/documents 20 %

test check at site for

physical verification.

Site Engineer

3. Detailed Soil

Investigation

a) Bore log 1. Depth of bore log

2. SPT Test

3. Collection of samples

As per Specification Contractor 100% at Field To witness 20% at Field Site Engineer



Page 2 of 23

S.

No.

Description

of Activity

Items to be Checked Tests/Checks to be

done

Ref. documents Check/Testing Counter Check/Test by

EMPLOYER

Accepting authority


b) Tests on samples As per tech. Specs. As per Specification Contractor

(Testing in NEA accepted

Lab)

100% by testing lab

(Reports to be signed by

Testing person & Checking

person)

Review of lab test results

(All soil reports to have

signature of EMPLOYER

executive reviewing the

report )

Site In-charge

based on the guide

line issued by

EMPLOYER as

Annex-6

c) Special foundations As per tech. Specs As per Specification Contractor

(Testing of samples in

NEA accepted Lab)

100% by testing lab

(Reports to be signed by

Testing person & Checking

person)

Review of lab test results

(All soil reports to have

signature of EMPLOYER

executive reviewing the

report )

Site In-charge

based on the guide

line issued by

EMPLOYER as

Annex-6

4 Revetment RR Masonry a) Size of Stone CPWD Spec. Contractor 100% physical

verification per source

Physical verification on

random basis

Site Engineer

b) Water absorption -Do- -Do-

(Testing in NEA accepted

Lab)

1 sample/ source Review of Lab Test results -Do-

c) Cement : sand

ratio in mortar

As per Specification Contractor 100% Physical verification in

random.

-Do-



Page 3 of 23

S.

No.

Description

of Activity


done


Employer

Accepting

authority in

Employer Agency Extent

5 Benching Checking of Reduced

Level

Reduced Level As per approved

drawings

Contractor 100% 100% by Site Engineer and

20% by Line In-charge

Site In-charge

6. Tower

Foundation

A) Materials

1. Cement

1. Brand approval Cement of NEA

approved brands may

be procured.

Contractor 100% Any new brand cement

proposed by Contractor shall

be assessed by NEA.

NEA

2. Physical tests As per document at

Annexure-I of this FQP

Contractor

Samples to be taken jointly

with Employer and tested

at NEA approved lab

Review of 100% MTC’s

and one sample for every

batch number of

manufacturer.

100% review of lab test

results and MTC.

Test results shall be sent by

the Lab. by E-mail directly to

Employer; further, hard copy

of test certificate shall also

be sent by the Lab directly to

Employer by postal Address.

Site In-charge

3. Chemical Tests

Chemical

composition of

Cement

-do- Contractor Review of all MTC’s 100% review of MTC test

results

Site In-charge



Page 4 of 23

S.

No.

Description

of Activity

Items to be Checked Tests/Checks to

be done


EMPLOYER

Accepting authority

of EMPLOYER

Agency Extent

2. a) Reinforcement

Steel

1. Source

approval

May be procured either

from main producers

directly or through the

authorized dealers who

can produce MTC from

main producers with

traceability.

Contractor 100% Material shall be supplied

from Main Producers /

authorized dealers.

Site In-charge

2. Physical and

Chemical

analysis test

As per annexure-2 of this

FQP

Contractor to submit MTC 100% MTC’s

One sample* / 500MT /

Manufacturer shall be

jointly sealed by Employer

and tested at NEA

approved Lab. * Note: All

sizes of 10mm and above

shall be taken for testing

in every 500MT.

100% review of MTC.

Review of Lab test results.

Test results shall be sent by

the Lab. by E-mail directly to

NEA; further, hard copy of

test certificate shall also be

sent by the Lab. directly to

NEA by postal Address.

Site In-charge

2. b) Miscellaneous

structural steel .

Source Approval. Source with material

meeting Specification

contractor As proposed by

contractor

To verify documents. Site In charge



Page 5 of 23

S.

No.

Description

of Activity


done


EMPLOYER

Accepting authority


3. Coarse

Aggregates

1. Source approval Source with materials


Contractor Proposed by the

Contractor, indicating the

location of the quarry and

based on the test results of

Joint samples tested at

NEA accepted Lab.

To review the proposal

based on the documents

Site In-charge

Once approved, the

particular quarry

shall be used for all

the running

contracts under

various packages.

2. Physical tests As per document at

Annexure-3 of this FQP

Contractor One sample per 1000 cum

or part thereof per source

for 765KV & above TL and

One sample per 500 cum


for 500KV & below TL ,

Samples to be tested by

Contractor in NEA

approved lab


results.

Out of these 100% samples,

Employer shall witness at

TPL, 5 samples selected at

random, spread during the

overall execution period of

contract.

Site In charge.

4. Fine aggregate 1. Source approval Source with materials


Contractor Proposed by the

Contractor, indicating the

location of the quarry and

based on the results of

Joint samples tested in

NEA accepted lab.

To review the proposal

based on the documents.

Project In-charge

Once approved, the

particular quarry

shall be used for all

the running

contracts under

various packages.

S.

No.

Description

of Activity

Items to be Checked

Tests/Checks to be

done

Ref. documents

Check/Testing Counter Check/Test by

EMPLOYER

Accepting authority

of EMPLOYER

Agency Extent



Page 6 of 23

2. Physical test As per Annexure-4 of

this FQP

Contractor One sample per 1000 cum


for 765KV & above TL and

One sample per 500 cum


for 500KV & below TL ,

Samples to be tested by

Contractor in NEA

approved lab


results.

Out of these 100% samples,

NEA shall witness at TPL, 5

samples selected at random,

spread during the overall

execution period of contract.

Site In charge.

5. Water 1. Cleanliness (Water

shall be fresh & clean)

Specification Contractor 100% visual check at Field Verification at random Site Engineer

2. PH Value - do - Contractor at site with calibrated PH meter or any other approved method

One sample per source 100% review of the test results

Ph not less than 6

Site Engineer

B) Foundation

Classification

1. Visual observation

of soil strata

2. Ground water

level

3. History of water

table in adj.

Area/surface

water

4. Soil Investigation

wherever required

Specification Contractor 100% at Field 100% at Field a. [other than b & c

locations below]

Recommendation by

Site Engineer to be

approved by Site in-

charge after visiting

at least 5% locations

b. In case of

WBC/SFR/FS / ULE

/ Raised Chimney

based on

recommendation by

Site In-charge, to be

approved by NEA

after visiting at least

5% locations.

c. For Spl. Fdns.

(shallow depth, pile



Page 7 of 23

foundation, well

foundation etc.)

Acceptance by

Regional head.

S.

No.

Description

of Activity


done


EMPLOYER

Accepting authority


C) Concrete

Works

a)Before

concreting

1. Bottom of

excavated earth

Depth of foundation Construction Drgs. Contractor 100% at Field 100% check by Employer Site Engineer

2.P.C.C Grade ,

thickness & Size

Completeness IS:456 and NEA

approved construction

drawings & specification.

Joint Inspection by NEA and

CONTRACTOR

For all locations For all locations Site Engineer

3. Stub setting 1) Centre Line Construction Drgs -do- -do- -do- *_* -do-

2) Diagonals -do- -do- -do- -do- *_* -do-

3) Level of stubs -do- -do- -do- -do- *_* -do-

4.Reinforcement steel

Placement Bar bending schedule. -do- -do- -do- *_* -do-

*_* At least 5%

locations shall be

cross verified by

immediate

Reporting Officer /

Site In-charge, at

random with respect

to stub setting and

reinforcement steel



Page 8 of 23

placement.

S.

No.

Description

of Activity


done


EMPLOYER

Accepting authority


b) During

concreting

1. Workability Slump test Range 25 mm to 55 mm

refer document at

Annexure-5 of this FQP

Contractor Minimum One per day per

location

check at random Site Engineer

2. Concrete Strength Cubes Comp Strength As per annexure-5 of

this FQP

Contractor

Casting of cubes at site.

Cubes to be tested for 28

days strength at NEA

appd. Lab /NEA Lab/At site

(if testing machine installed

by contractor is duly

calibrated by NABL Lab.)

Cubes at 100% location are

to be taken in presence of

Employer officials

One sample of 3 cubes in

each tower locations if all

the legs are cast

continuously without

interruption. If otherwise,

additional 3 cubes to be

taken for every subsequent

continuous casting case.

Note: It is to be ensured

that in every case 3

samples shall be selected

in such a way that one

each from start, middle and

end of the casting process.

Normally testing shall be

carried out at the cube

Testing Facility installed by

contractor at NEA premises,

in the witness of Employer.

Alternatively, samples shall

be tested at NEA approved

Labs/ NEA Lab. In this case,

test results shall be sent by

the Lab, by E-mail directly to

NEA; further, hard copy of

Test Certificate shall also be

sent by the Lab directly to

NEA by Postal Address.

Further, Employer to witness

testing on 20% samples and

also to review 100% test

results.

Site Engineer.

Out of testing on

10% samples to be

witness at TPL by

Employer Site

Engineer and at

least 5% samples at

random, shall be

witnessed by Site

In-charge.

In-case of Site/ NEA

Lab, 100% witness

by Employer

Representative.



Page 9 of 23

S.

No.

Description

of Activity


done


EMPLOYER

Accepting

authority of

EMPLOYER Agency Extent

3.Chimney Concrete Top level of chimney

concrete w.r.t GL

Appd. Drgs. Contractor 100% at Field 100% check by Employer Site Engineer

c) After

Concreting

Back filling Completeness As per Specification Contractor 100% 100% Site Engineer

7. Pile

Foundations

Refer FQP OF

TRANSMISSION

LINE PILE

FOUNDATION

8. Tower

Erection

1. Materials of

Tower member/bolts

&

nuts/washers/accesso

ries

Visual checking for

1. Stacking

2. Cleanliness

3. Galvanizing

4. Damages

Appd. Drgs./BOM Contractor 100% at stores 100% verification of records Site Engineer

2. Erection of Super-

structure

1. Sequence of

erection

As per Appd. Drgs./

specification

Contractor 100% at field Random

Site Engineer

2. Check for

completeness

As per Appd. Drgs./

specification

Contractor 100% at field 25% by Site Engr and random

by Site Incharge.

Site In charge



Page 10 of 23

S.

No.

Description

of Activity


done


EMPLOYER

Accepting

authority of


3. Tightening of

nuts and bolts

-do- -do- -do- -do- -do-

4. Check for

verticality


5. Tack welding for

bolts & nuts

Specification Contractor 100% at Field -do- Site Engineer

3. Tower footing

resistance (TFR)

TFR at locations

before and after

earthing.

Specification Contractor 100% at Field 20% locations to be verified Site In-charge

9 Earthing Pipe Type Salt & charcoal As per approved

drawings

Contractor 100% Checking of record 100%

and physical verification in

Random

Site Engineer

Counterpoise Type Length & Depth of

earth electrode.

As per approved

drawings

Contractor 100% ---do--- Site Engineer



Page 11 of 23

S.

No.

Description

of Activity


done


EMPLOYER

Accepting

authority of


10 Stringing 1. Materials

a) Insulators 1. Visual check for

cleanliness/glazing/

cracks/and white

spots.

Specification Contractor 100% at Field 100% verification of records

and to carry Physical

verification random checks

10%

Site Engineer

2. IR Value Minimum acceptable

value 2000 Mega

ohm

-do- Test shall be carried on

100% insulators using

5/10 kV (DC) Megger

100 % by Contractor and

record review by Employer

and joint witnessing by

Employer on 05% insulator

Site In-charge

3. Traceability

(Make/batch

No./Locations

where installed)

Packing list/CIP Contractor 100% at field 100% Review of records Site Engineer



Page 12 of 23

S.

No.

Description

of Activity


done


EMPLOYER

Accepting

authority of


b) Conductor On receipt,

1. Visual check of

drum.

Packing list/CIP Contractor 100% at stores 20% check Site Engineer

2. Check for seals

and Employer

signed sticker on

outer end


3. Check depth

from top of flange

to the top of the

outer most layer


c) Earth wire Check for seals at

both ends

Packing list/ CIP Contractor 100% at stores 20% check -do-

2. Field activity

a) Before Stringing Readiness for

stringing

Stringing procedures

as per specification

Contractor Readiness certificate to

be submitted by the

Contractor

Review of Certificate Site In-charge



Page 13 of 23

S.

No.

Description

of Activity


done


EMPLOYER

Accepting

authority of


b) During stringing (Conductor/Earth-

wire)

1. Scratch/cut

check (Visual)

Appd. Drawings/

Specn.

Contractor 100% at Field 100% verification of record &

20% Field check

Site Engineer

2. Repair sleeve -do- -do- -do- -do- -do-

3. Mid span Joints -do- -do- -do- -do- -do-

4. Guying (in case

of towers not

designed for one

side stringing)

Appd. Guying

arrangement/ Specn.

-do- -do- 100% Site Engineer

c) After stringing Check for,

1. Sag/Tension Stringing Chart /

tower Spotting data

-do- -do- 100% verification of record &

20% field check

Site Engineer

2. Electrical

clearances

As per Appd. Drgs./

specifications

-do- -do- -do- -do-



Page 14 of 23

S.

No.

Description

of Activity


done


EMPLOYER

Accepting

authority of


i) Ground

clearance


ii) Live metal

clearance etc.


3. Jumpering -do- -do- -do- -do- -do-

4. Copper bond As per Appd.

Drgs./Specification

Contractor 100% at Field 100% record & Field

Check 20%

Site Engineer

5a). Placement

of spacer/damper

As per Specn./Drgs/

placement chart

-do- -do- -do- -do-

5b) Tightening of

bolts & nuts as per

manufacturer

recommendations.

-do - -do- 100% with fixed torque

wrench.

-do- -do-

11. Final Testing

a) Pre-

commissioni

ng of lines

a) Readiness of

lines for pre-

commissioning

1. Completeness of

line.

2. Meggar test of

line

latest pre-

commissioning

procedures

Joint inspection by

Employer and

Contractor

100% 100% Site In-charge



Page 15 of 23

S.

No.

Description of

Activity

Items to be

Checked

Tests/Checks to be

done


EMPLOYER

Accepting

authority of


b)Commissioni

ng of line

Readiness of

lines for

commissioning

1. Digital

photograph of each

tower to ascertain

the completeness

of tower.

a) Latest pre-

commissioning

procedures

b) Pre-

commissioning

Report

c) NEA clearance

-do- -do- -do- -do-



Page 16 of 23

Annex-1 (Sheet 01 of 03)

ACCEPTANCE CRITERIA AND PERMISSIBLE LIMITS FOR CEMENT

ORDINARY PORTLAND CEMENT

S. No.

Name of the test Ordinary Portland Cement 33 grade as per IS 269

Ordinary Portland Cement 43 grade as per IS 8112


Remarks

a) Physical tests To be conducted in apprd. Lab

(i) Fineness Specific surface area shall not be less than 225 sq.m. per Kg. or 2250 Cm2/gm.

Specific surface area shall not be less than 225 sq.m. per Kg or 2250 Cm2/gm.

Specific surface area shall not be less than 225 sq.m. per Kg or 2250 Cm2/gm.

Blaine’s air permeability method as per IS 4031 (Part-2) / Sieve analysis as per IS 4031 (part-3)

(ii) Compressive strength

72 ± 1 hour : Not less than 16 Mpa (16 N/mm2)

72 ± 1 hour : Not less than 23 Mpa ( 23 N/mm

2)

72 ± 1 hour : Not less than 27Mpa (27 N/mm

2)

As per IS 4031 (Part-6)


168 ± 2 hour : Not less than 33Mpa ( 33 N/mm

2)

168 ± 1 hour : Not less than 37Mpa ( 37 N/mm

2)



2)


2)

(iii) Initial & Final setting time

Initial setting time : Not less than 30 minutes



As per IS 4031 (Part-5)

Final setting time : Not more than 600 minutes



-do-

(iv) Soundness Unaerated cement shall not have an expansion of more than 10mm when tested by Le Chatlier and 0.8% by Autoclave test.

Unaerated cement shall not have an expansion of more than 10mm when tested by Le Chatlier and 0.8% by Autoclave test

Unaerated cement shall not have an expansion of more than 10mm when tested by Le Chatlier and 0.8% by Autoclave test.

Le Chatlier and Autoclave test as per IS 4031 (Part-3)



Page 17 of 23


S. No.

Name of the test Ordinary Portland Cement 33 grade as per IS 269



Remarks

b) Chemical composition tests Review of MTCC only

a) Ratio of percentage of lime to percentage of silica, alumina & iron oxide 0.66 to 1.02

a) Ratio of percentage of lime to percentage of silica, alumina & iron oxide 0.66 to 1.02

a) Ratio of percentage of lime to percentage of silica, alumina & iron oxide 0.80 to 1.02%

b) Ratio of percentage of alumina to that of iron oxide Minimum 0.66%

a) Ratio of percentage of alumina to that of iron oxide Minimum 0.66

a) Ratio of percentage of alumina to that of iron oxide Minimum 0.66%

c) Insoluble residue, percentage by mass Max. 4.00%



d) Magnesia percentage by mass Max. 6%



e) Total sulphur content calculated as sulphuric anhydride (SO3), percentage by mass not more than 2.5 and 3.0 when tri-calcium aluminate percent by mass is 5 or less and greater than 5 respectively.

e) Total sulphur content calculated as sulpuric anhydride (SO3), percentage by mass not more than 2.5 and 3.0 when tri-calcium aluminate percent by mass is 5 or less and greater than 5 respectively.

e) Total sulphur content calculated as sulpuric anhydride (SO3), percentage by mass not more than 2.5 and 3.0 when tri-calcium aluminate percent by mass is 5 or less and greater than 5 respectively.

f) Total loss on ignition shall not be more than 5 percent





Page 18 of 23


S. No.

Name of the test Remarks

2. PORTLAND POZZOLANA CEMENT AS PER IS 1489/2005

a) Physical tests i) Fineness Specific surface area shall not be less than 300 sq.m. per Kg. or 3000 Cm

2/gm

To be conducted in NEA

approved Lab

ii) Compressive strength a) 72 ± 1 hour : Not less than 16 Mpa (16 N/mm2)

b) 168 ± 2 hour : Not less than 22 Mpa (22 N/mm2)

c) 672 ± 4 hour : Not less than 33 Mpa (33 N/mm2)

iii) Initial & Final setting time Initial setting time : Not less than 30 minutes


iv) Soundness Un aerated cement shall not have an expansion of more than 10mm Le chatlier test and 0.8% by Autoclave test as per IS 4031 (Part-3)

b) Chemical composition tests

a) Magnesia percentage by mass Max. 6% Review of MTCC only

b) Insoluble material, percentage by mass x + 4 (100-x)/100 where x is the declared % of pozzolana in the PPC

-do-

c) Total sulphur content calculated as sulpuric anhydride (SO3), percentage by mass not more than 3.0

-do-

Total loss on ignition shall not be more than 5 percent



Page 19 of 23

Annex-2

ACCEPTANCE CRITERIA AND PERMISSIBLE LIMITS FOR REINFORCEMENT STEEL AS PER IS 1786-1985 Edition-4.3 (2004-12)

S. No.

Name of the test Fe 415

Fe 500

i) Chemical analysis test

Carbon 0.30 Percent Maximum 0.30 Percent Maximum

Sulphur 0.060 Percent Maximum 0.055 Percent Maximum

Phosphorus 0.060 Percent Maximum 0.055 Percent Maximum

Sulphur & Phosphorus 0.11 Percent Maximum 0.105 Percent Maximum

ii) Physical tests

a) Tensile Strength Minimum

10% more than actual 0.2% proof stress but not less than 485 N/Sq.mm.

8 % more than actual 0.2% proof stress but not less than 545 N/Sq.mm

b) 0.2% of proof stress/Yield stress Minimum, N/mm

2

415 500

c) Elongation percent , Minimum 14.5 12

iii) Bend & Rebend tests Pass Pass



Page 20 of 23

Annex-3 ACCEPTANCE CRITERIA AND PERMISSIBLE LIMITS FOR COARSE AGGREGATES AS PER IS 383

3. Coarse Aggregates

i) Physical Tests

a) Determination of particles size

a. IS Sieve Designation

%age passing for Single-Sized Aggregate of nominal size

Percentage Passing for graded Aggregate of nominal size

40 mm 20 mm 16 mm 12.5 mm 10 mm 40 mm 20 mm 16 mm 12.5 mm

63 mm 100 - - - - - - - -

40 mm 85 to 100 100 - - - 95 to 100 100 - -

20 mm 0 to 20 85 to 100 100 - - 30 to 70 95 to 100 100 100

16 mm - - 85 to 100 100 - - - 90-100 -

12.5 mm - - - 85 to 100 100 - - - 90 to 100

10 mm 0 to 5 0 to 20 0 to 30 0 to 45 85 to 100 10 to 35 25 to 55 30 to 70 40 to 85

4.75 mm - 0 to 5 0 to 5 0 to 10 0 to 20 0 to 5 0 to 10 0 to 10 0 to 10

2.36 mm - - - - 0 to 5 - - - -

b. Flakiness index Not to exceed 25%

c. Crushing Value Not to exceed 45%

d. Presence of deletrious material Total presence of deleterious materials not to exceed 5%

e. Hardness Abrasion value not more than 50%, Impact value not more than 45%

f. Soundness test (for concrete work subject to frost action)

Not to exceed 12% when tested with sodium sulphate and 18% when tested with magnesium sulphate



Page 21 of 23

Annex-4

ACCEPTANCE CRITERIA AND PERMISSIBLE LIMITS FOR FINE AGGREGATES AS PER IS 383

4. Fine aggregates

i) Physical Tests IS Sieve Designation

Percentage passing for

a) Determination of particle size F.A. Zone I F.A. Zone II F.A. Zone III

10 mm 100 100 100

4.75 mm 90-100 90-100 90-100

2.36 mm 60-95 75-100 85-100

1.18 mm 30-70 55-90 75-100

600 microns 15-34 35-59 60-79

300 microns 5 to 20 8 to 30 12 to 40

150 microns 0-10 0-10 0-10

b) Silt content Not to exceed 8% Not to exceed 8% Not to exceed 8%

c) Presence of deleterious material Total presence of deleterious materials shall not exceed 5%

d) Soundness Applicable to concrete work subject to frost action

12% when tested with sodium sulphate and 15% when tested with magnesium sulphate



Page 22 of 23

Annex-5

ACCEPTANCE CRITERIA AND PERMISSIBLE LIMITS FOR CONCRETE WORK

1) Concrete a) Workability Slump shall be recorded by slump cone method and it shall between 25-55 mm.

b) Compressive strength For nominal (volumetric) concrete mixes compressive strength for 1:1.5:3 (Cement : Fine aggregates : Coarse aggregates) concrete 28 days strength shall be min 265Kg/cm2 and for 1:2:4 (Cement: Fine Aggregate: Coarse Aggregate) nominal mix concrete 28 days strength shall be min 210Kg/cm2.

Notes:

1) ACCEPTANCE CRITERIA BASED ON 28 DAYS COMPRESSIVE STRENGTHS FOR NOMINAL MIX CONCRETE:

a) On the basis of mandatory lab test result, in case of actual average compressive strength being less than specified strength but up to 70% of specified strength, concrete may be accepted and the rate payable shall be in the same proportion as the actual average compressive strength bears to specified compressive strength.

However, in case cube strength of any one leg of any location is found to be between 70% to 100% of specified value, all four legs of the respective location shall be analyzed. Root cause analysis has to be carried out with NDT method to verify the quality and strength of the foundations. If the results are not acceptable penalty such as re-doing of complete foundation/legs, cost towards supervision charges shall be levied from the contractor towards the sub-standard work, with the approval of Regional Head.

b) If the actual average strength of accepted sample is less than 70% of specified strength, the Site -in-charge shall reject the defective portion of work represent by sample and nothing shall be paid for the rejected work. Remedial measures necessary to retain the structure shall be taken at the risk and cost of contractor. If, however, the Engineer-in-charge / Project In-charge so desires, he may order additional tests to be carried out to ascertain if the structure can be retained/rectified. All the charges in connection with these additional tests shall be borne by the Contractor.

2) 53 Grade cement shall be used after obtaining specific approval of the Engineer in charge.

3) Portland slag cement conforming to IS:455 may be used as per Technical Specification.



Page 23 of 23

General Notes:

1) This standard Field Quality Plan is not to limit the supervisory checks which are otherwise required to be carried out during execution of work as per drawings/Technical specifications etc.

2) Contractor shall be responsible for implementing/documenting the SFQP. Documents shall be handed over by the contractor to Employer after the completion of the work.

3) Acceptance criteria and permissible limits for tests are indicated in the Annexures. However for further details/tests specification and relevant Indian standards shall be referred.

4) Tests as mentioned in this FQP shall generally be followed.


SECTION-V



SECTION-V

CONTENTS

Clause No. Description Page No.

1.0

Technical Description of ACSR Conductor

1

2.0 Tests and Standards 4

Annexure-A : Standard Technical Particulars

Annexure-B : Tests on Conductor

Annexure-C : Drum Drawings


SECTION V VOL II

PAGE 1


SECTION-V

1. Technical Description of ACSR Conductor

1.1 Details of Conductor

1.1.1 The ACSR Conductor shall generally conform to IEC: 61089/ IS: 398 (relevant

part)/ ASTM:B-232 except where otherwise specified herein.

1.1.2 Standard Technical Particulars

The Standard Technical Particulars (STP) of the ACSR conductors are

enclosed at Annexure-A of this section. The values indicated in the STP are

the minimum and/or maximum values required to be met by the supplier.

1.2 Workmanship

1.2.1 All the aluminum and steel strands shall be smooth, uniform and free from all

imperfections, such as spills and splits, die marks, scratches, abrasions, etc.,

after drawing and also after stranding.

1.2.2 The finished conductor shall be smooth, compact, uniform and free from all

imperfections including kinks (protrusion of wires), wire cross over, over

riding, looseness (wire being dislocated by finger/hand pressure and/or

unusual bangle noise on tapping), material inclusions, white rust, powder

formation or black spot (on account of reaction with trapped rain water etc.),

dirt, grit etc.

1.2.3 The steel strands shall be hot dip galvanised and shall have a minimum zinc

coating as indicated in the STP. The zinc coating shall be smooth, continuous,

of uniform thickness, free from imperfections and shall withstand number of

dips in Standard Preece test as indicated in STP. The steel wire rods shall be

of such quality and purity that, when drawn to the size of the strands

specified and coated with zinc, the finished strands and the individual wires

shall be of uniform quality and have the same properties and characteristics

as prescribed in IEC: 60888.

1.2.4 The steel strands shall be preformed and post formed in order to prevent

spreading of strands in the event of cutting of complete core. Care shall be

taken to avoid, damages to galvanisation during pre-forming and post-

forming operation.


SECTION V VOL II

PAGE 2

1.3 Joints in Wires

1.3.1 Aluminium Wires

1.3.1.1 During stranding, no aluminum wire welds shall be made for the purpose of

achieving the required conductor length.

1.3.1.2 No joints shall be permitted in the individual wires in the outer most layer of

the finished conductor. However joints are permitted in the inner layer of the

conductor unavoidably broken during stranding provided such breaks are

not associated with either inherently defective wire or with the use of short

lengths of aluminium wires. Such joints shall not be more than four (4) per

conductor length and shall not be closer than 15 meters from joint in the same

wire or in any other aluminium wire of the completed conductor.

1.3.1.3 Joints shall be made by cold pressure butt welding and shall withstand a

stress of not less than the breaking strength of individual strand as per STP.

1.3.2 Steel Wires

There shall be no joint of any kind in the finished wire entering into the

manufacture of the strand. There shall also be no strand joints or strand

splices in any length of the completed stranded steel core of the conductor.

1.4 Tolerances

The manufacturing tolerances to the extent indicated in the STP shall be

permitted in the diameter of individual aluminium and steel strands and lay-

ratio of the conductor.

1.5 Materials

1.5.1 Aluminium

The aluminium strands shall be hard drawn from electrolytic aluminium rods

having purity and copper content as per the values indicated in the STP. They

shall have the same properties and characteristics as prescribed in IEC: 60889.

1.5.2 Steel

The steel wire strands shall be drawn from high carbon steel wire rods

produced by either the acid or the basic open-hearth process, the electric

furnace process, or the basic oxygen process and shall conform to the

chemical composition indicated in the STP.


SECTION V VOL II

PAGE 3

The Steel wire strands shall have the same properties and characteristics as

prescribed for regular strength steel wire in IEC : 60888.

1.5.3 Zinc

The zinc used for galvanizing shall be electrolytic High Grade Zinc of purity

as indicated in the STP. It shall conform to and satisfy all the requirements of

IS:209.

1.6 Standard Length

1.6.1 The standard length of the conductor shall be as indicated in the STP. All

lengths outside this limit of tolerance shall be treated as random lengths. Not

less than 90% of the total quantity of the conductor shall be supplied in

standard lengths.

1.6.2 Random lengths will be accepted provided no length is less than 70% of the

standard length and the total quantity of such random lengths shall not be

more than 10% of the total quantity ordered. At any point, the cumulative

quantity supplied of such random lengths shall not be more than 12.5% of the

total cumulative quantity supplied including such random lengths. However,

the last 20% of the quantity ordered shall be supplied only in standard

lengths as specified.

1.6.3 The purchaser reserves the right to place orders for the lengths above the

standard length on the same terms and conditions applicable for the standard

lengths during the pendency of the Contract.

2.0 Tests and Standards

2.1 Type Tests

The following tests shall be conducted on a sample/samples of the

conductor(s) required under the package from each stranding machine from

which the conductor is to be manufactured & supplied:

a) DC resistance test on stranded conductor

As per Annexure-B

b) UTS test on stranded conductor

c) Corona extinction voltage test (dry) *

d) Radio interference voltage test (dry) *

e) Stress-Strain Test

* applicable for 220 kV or above voltage level only


SECTION V VOL II

PAGE 4

2.1.1 Type tests specified under Clause 2.1 shall not be required to be carried out if

supplier has conducted these tests earlier on the same conductor & same

bundle configuration (applicable for tests ‘c’ & ‘d’) and valid type test

certificates are available. The test certificate shall be considered valid if,

i) Tests conducted earlier is either conducted in accredited laboratory

(accredited based on ISO/IEC vide 25/17025 or EN 45001 by the National

accreditation body of the country where laboratory is located) or

witnessed by the representative(s) of utility and

ii) Tests conducted on the samples of conductor manufactured from same

stranding machine within 3 (three) years prior to the date of

commencement of manufacturing for the package. However, the

manufacturing of the conductor for the package can be carried till 3

(three) years from the date of type testing.

In case the tests have been conducted earlier than the above stipulated period

or carried out on another stranding machine or in the event of any

discrepancy in the test report (i.e., any test not applicable due to any

design/manufacturing change including substitution of components or due to

non-compliance with the requirement stipulated in the Technical

Specifications), the tests shall be conducted by the supplier at no extra cost to

the purchaser. Also, in case, manufacturing (scheduled/actual) is beyond the 3

(three) years from the date of type testing, supplier has to repeat the above

type tests at no extra cost to the purchaser.

2.2 Acceptance Tests

a) Visual and dimensional check on drum

As per Annexure-B

b) Visual check for joints, scratches etc. and length

measurement of conductor by rewinding

c) Measurement of diameters of individual Steel

and Aluminium strands

d) Check for lay-ratios of various layers

e) Galvanizing test on steel strands

f) Torsion and Elongation tests on steel strands

g) Breaking load test on steel and Aluminium

strands

IEC : 60888 & 60889

h) Wrap test on Steel & Aluminium strands IEC : 60888 & 60889

i) DC resistance test on Aluminium strands IEC : 60889


SECTION V VOL II

PAGE 5

j) Procedure qualification test on welded joint of

Aluminium strands

As per Annexure-B

k) Drum strength test (steel drum) As per Annexure-B

l) Barrel Batten strength test (wooden drum) As per Annexure-B

Note: All the above tests except (j) shall be carried out on Aluminium and

steel strands after stranding only.

2.3 Routine Test

a) Check to ensure that the joints are as per Specification

b) Check that there are no cuts, fins etc. on the strands

c) Check that drums are as per Specification

d) All acceptance test as mentioned above to be carried out on aluminium

and steel strands of 20% of drums

2.4 Tests During Manufacture

a) Chemical analysis of zinc used for galvanizing

As per Annexure-B

b) Chemical analysis of Aluminium used for

making Aluminium strands

c) Chemical analysis of steel used for making

steel strands

2.5 Testing Expenses

2.5.1 In the event of type testing, bidder shall ensure that adequate facilities are

available in the laboratories and the tests can be completed in these

laboratories within the time schedule.

2.5.3 In case of failure in any type test, the supplier is either required to

manufacture fresh sample lot and repeat the entire tests successfully once or

repeat that particular type test three times successfully on the sample selected

from the already manufactured lot at his own expense. In case a fresh lot is

manufactured for testing then the lot already manufactured shall be rejected.

2.5.4 The entire cost of testing for the type, acceptance, routine tests and tests

during manufacture specified herein shall be treated as included in the

quoted unit price of conductor, except for the expenses of the

inspector/purchaser's representative.


SECTION V VOL II

PAGE 6

2.5.5 In case of failure in any type test, if repeat type tests are required to be

conducted, then all the expenses for deputation of inspector/purchaser's

representative shall be to the supplier’s account. Also, if on receipt of the

supplier's notice of testing, the purchaser's representative does not find the

test samples or testing facilities/equipments ready for testing, the expenses

incurred by the purchaser for re-deputation shall be to the supplier’s account.

2.6 Additional Tests

2.6.1 The purchaser reserves the right of having at his own expenses any other

test(s) of reasonable nature carried out at supplier’s premises, at site or in any

other place in addition to the aforesaid type, acceptance and routine tests to

satisfy himself that the materials comply with the Specifications.

2.6.2 The purchaser also reserves the right to conduct all the tests mentioned in this

specification at his own expense on the samples drawn from the site at

supplier’s premises or at any other test centre. In case of evidence of non

compliance, it shall be binding on the part of supplier to prove the compliance

of the items to the technical specifications by repeat tests, or correction of

deficiencies, or replacement of defective items all without any extra cost to the

purchaser.

2.7 Sample Batch For Type Testing

2.7.1 In case the type tests are required to be carried out, the samples for type

testing shall be manufactured in accordance with the Standard Manufacturing

Quality Plan.

2.7.2 The supplier shall offer at least three drums for selection of sample required

for conducting all the type tests.

2.7.3 The supplier is required to carry out all the acceptance tests successfully in

presence of purchaser’s representative before sample selection.

2.8 Test Reports

2.8.1 In case type tests have been carried out earlier by the supplier and valid type

test reports are available as specified in clause 2.1.1 above, the supplier shall

submit one copy of the test report along with approval letter issued by utility.

2.8.2 In case fresh type tests have been carried out under the package, the type test

reports shall be furnished in original along with two copies. One copy will be

returned duly certified by the purchaser.


SECTION V VOL II

PAGE 7

2.8.2 The commercial production of the conductor can be taken up by the supplier

after clearance from the purchaser.

2.8.3 Record of routine test reports shall be maintained by the supplier at his works

for periodic inspection by the purchaser’s representative.

2.8.4 Test Certificates of tests during manufacture shall be maintained by the

supplier. These shall be produced for verification as and when desired by the

purchaser.

2.9 Inspection

2.9.1 The purchaser’s representative shall at all times be entitled to have access to

the works and all places of manufacture, where conductor shall be

manufactured and representative shall have full facilities for unrestricted

inspection of the supplier’s works, raw materials and process of manufacture

for conducting necessary tests as detailed herein.

2.9.2 The supplier shall keep the purchaser informed in advance of the time of

starting and of the progress of manufacture of conductor in its various stages

so that arrangements can be made for inspection.

2.9.3 No material shall be dispatched from its point of manufacture before it has

been satisfactorily inspected and tested, unless the inspection is waived off by

the purchaser in writing. In the latter case also the conductor shall be

dispatched only after satisfactory testing for all tests specified herein have

been completed.

2.9.4 The acceptance of any quantity of material shall in no way absolve the

supplier of any of his responsibilities for meeting all requirements of the

Specification, and shall not prevent subsequent rejection if such material is

later found to be defective.

2.10 Test Facilities

2.10.1 The following test facilities shall be available at the supplier’s works:

a) Various testing and measuring equipment for carrying out specified

acceptance tests, routine tests and tests during manufacture inter alia

including tensile testing machine, resistance measurement facilities,

torsion & wrap testing machine, dimension checking instruments viz.

digital vernier and micrometer etc., galvanizing test instruments viz.

digital elcometer and standard preece test etc., burette, digital

thermometer, barometer etc.


SECTION V VOL II

PAGE 8

b) Digital milli/micro ohm meter along with standard resistance for

calibration of resistance bridges.

c) Spectrometer, if supplier has its own properzi mill

c) Finished conductor shall be checked for length verification and surface

finish on separate rewinding machine at reduced speed (variable from 8

to 16 meters per minute). The rewinding facilities shall have appropriate

clutch system and free of vibrations, jerks etc. with traverse laying

facilities.

2.11 Packing

2.11.1 The conductor shall be supplied in non-returnable, strong, wooden drums

provided with lagging of adequate strength, constructed to protect the

conductor against all damage and displacement during transit, storage and

subsequent handling and stringing operations in the field. The Supplier shall

be responsible for any loss or damage during transportation handling and

storage due to improper packing. The drums shall generally conform to

IS:1778 or equivalent, except as otherwise specified hereinafter.

2.11.2 One standard length shall be wound on each drum. The drums shall be

suitable for wheel mounting and for letting off the conductor under a

minimum controlled tension of the order of 5 KN.

2.11.3 The standard drawing of the drum for conductor is enclosed with the

specification. The Bidder shall supply the conductor in the drum conforming

to the specification drawing.

2.11.4 All wooden components shall be manufactured out of seasoned soft wood,

free from defects that may materially weaken the component parts of the

drums. Preservative treatment shall be applied to the entire drum with

preservatives of a quality which is not harmful to the conductor.

2.11.5 The flanges shall be of two ply construction with each ply at right angles to

the adjacent ply and nailed together. The nails shall be driven from the inside

face flange, punched and then clenched on the outer face. The thickness of

each ply shall not vary by more than 3mm from that indicated in the figure.

There shall be at least 3 nails per plank of ply with maximum nail spacing of

75mm. Where a slot is cut in the flange to receive the inner end of the

conductor the entrance shall be in line with the periphery of the barrel.

2.11.6 The wooden battens used for making the barrel of the conductor shall be of

segmental type. These shall be nailed to the barrel supports with at least two

nails. The battens shall be closely butted and shall provide a round barrel


SECTION V VOL II

PAGE 9

with smooth external surface. The edges of the battens shall be rounded or

chamfered to avoid damage to the conductor.

2.11.7 Barrel studs shall be used for the construction of drums. The flanges shall be

holed and the barrel supports slotted to receive them. The barrel studs shall

be threaded over a length on either end, sufficient to accommodate washers,

spindle plates and nuts for fixing flanges at the required spacing.

2.11.8 Normally, the nuts on the studs shall stand protruded of the flanges. All the

nails used on the inner surface of the flanges and the drum barrel shall be

counter sunk. The ends of barrel shall generally be flushed with the top of the

nuts.

2.11.9 The inner cheek of the flanges and drum barrel surface shall be painted with a

bitumen based paint.

2.11.10 Before reeling, card board or double corrugated or thick bituminised water-

proof bamboo paper shall be secured to the drum barrel and inside of flanges

of the drum by means of a suitable commercial adhesive material. After

reeling the conductor, the exposed surface of the outer layer of conductor

shall be wrapped with water proof thick bituminised bamboo paper to

preserve the conductor from dirt, grit and damage during transport and

handling.

2.11.11 A minimum space of 75 mm for conductor shall be provided between the

inner surface of the external protective tagging and outer layer of the

conductor.

2.11.12 Each batten shall be securely nailed across grains as far as possible to the

flange, edges with at least 2 nails per end. The length of the nails shall not be

less than twice the thickness of the battens. The nails shall not protrude above

the general surface and shall not have exposed sharp, edges or allow the

battens to be released due to corrosion.

2.11.13 The nuts on the barrel studs shall be tack welded on the one side in order to

fully secure them. On the second end, a spring washer shall be used.

2.11.14 A steel collar shall be used to secure all barrel studs. This collar shall be

located between the washers and the steal drum and secured to the central

steel plate by welding.

2.11.15 Outside the protective lagging, there shall be minimum of two binder

consisting of hoop iron/galvanised steel wire. Each protective lagging shall

have two recesses to accommodate the binders.


SECTION V VOL II

PAGE 10

2.11.16 The conductor ends shall be properly sealed and secured on the side of one of

the flanges to avoid loosening of the conductor layers during transit and

handling.

2.11.17 As an alternative to wooden drum Bidder may also supply the conductors in

non-returnable painted steel drums or wood-Steel hybrid drums. After

preparation of steel surface according to IS:9954, synthetic enamel paint shall

be applied after application of one coat of primer. Wooden/Steel drum/Wood-

Steel hybrid drum will be treated at par for evaluation purpose and

accordingly the Bidder should quote in the package.

2.12 Marking

Each drum shall have the following information stenciled on it in indelible

ink along with other essential data :

(a) Contract/Award letter number.

(b) Name and address of consignee.

(c) Manufacturer’s name and address.

(d) Drum number

(e) Size of conductor

(f) Length of conductor in meters

(g) Arrow marking for unwinding

(h) Position of the conductor ends

(i) Barrel diameter at three locations & an arrow marking at the location

of the measurement.

(j) Number of turns in the outer most layer.

(k) Gross weight of drum after putting lagging.

(l) Tear weight of the drum without lagging.

(m) Net weight of the conductor in the drum.

(n) CIP/MICC No.

The above should be indicated in the packing list also.

2.13 Verification of Conductor Length

The purchaser reserves the right to verify the length of conductor after

unreeling. The quantity for verification shall be between a minimum of five

percent (5%) to a maximum of ten percent (10%) in a lot offered for

inspection. The actual quantity will be discussed and mutually agreed to by

the supplier & purchaser.


SECTION V VOL II

PAGE 11

2.14 Standards

2.14.1 The conductor shall conform to the following Standards, which shall mean

latest revisions, with amendments/changes adopted and published, unless

specifically stated otherwise in the Specification.

2.14.2 In the event of the supply of conductor conforming to standards other than

specified, the Bidder shall confirm in his bid that these standards are

equivalent to those specified. In case of award, salient features of comparison

between the standards proposed by the supplier and those specified in this

document will be provided by the supplier to establish their equivalence.

Sl.

No.

Indian Standard Title International

Standard

1. IS: 209 Specification for zinc BS:3436

2. IS: 398 Part-I Specification for Aluminium Conductors

for Overhead Transmission Purposes

IEC:61089

BS:215

3. IS:398 Part-II Aluminum Conductor Galvanised Steel

Reinforced

BS:215

IEC:61089

4. IS:398 Part-V Aluminum Conductor Galvanised Steel-

Reinforced For Extra High Voltage (400

KV) and above

IEC:61089

BS:215

5. IS : 1778 Reels and Drums for Bare Conductors BS:1559

6. IS : 1521 Method of Tensile Testing of Steel Wire ISO 6892

7. IS : 2629 Recommended Practice for Hot Dip

Galvanising of Iron and Steel

8. IS : 2633 Method of Testing Uniformity of Coating

on Zinc Coated Articles

9. IS : 4826 Galvanised Coating on Round Steel

Wires

IEC : 60888

BS:443

10. IS : 6745 Methods of Determination of Weight of

Zinc Coating of Zinc Coated Iron and

Steel Articles

BS:433

ISO 1460

11. IS : 8263 Method of Radio Interference Tests on

High Voltage Insulators

IEC: 60437

NEMA:107

CISPR

12. Zinc Coated steel wires for stranded

Conductors

IEC : 60888

13. Hard drawn Aluminium wire for

overhead line conductors

IEC : 60889

The standards mentioned above are available from:


SECTION V VOL II

PAGE 12


Name and Address

BS British Standards,

British Standards Institution

101, Pentonvile Road,

N - 19-ND

UK

IEC/CISPR International Electro technical Commission,

Bureau Central de la Commission,

electro Technique international,

1 Rue de verembe,

Geneva

SWITZERLAND

BIS/IS Bureau Of Indian Standards.

Manak Bhavan,

9, Bahadur Shah Zafar Marg,

New Delhi - 110001.

INDIA

ISO International Organisation for

Standardization.

Danish Board of Standardization

Danish Standardizing Sraat,

Aurehoegvej-12

DK-2900, Heeleprup,

DENMARK.

NEMA National Electric Manufacture Association,

155, East 44th Street.

New York, NY 10017

U.S.A.


SECTION V VOL II

PAGE 1

Annexure-A

Standard Technical Particulars for ACSR Conductors

Sl. Description Unit Standard Technical Particulars Conductors

ACSR

LAPWING

ACSR

BERSIMIS

ACSR

SNOWBIRD

ACSR

MOOSE

ACSR

ZEBRA

ACSR

BISON

1.0 Construction

1.1 Stranding and wire diameter

a) Aluminium wire 45/4.78 mm 42/4.57 mm 42/3.99 mm 54/3.53 mm 54/3.18 mm 54/3.00 mm

b) Steel wire 7/3.18 mm 7/2.54 mm 7/2.21 mm 7/3.53 mm 7/3.18 mm 7/3.00 mm

1.2 Layer & no. of wire

a) Steel core 1 1 1 1 1 1

b) 1st steel layer 6 6 6 6 6 6

c) 1st Aluminium layer 9 8 8 12 12 12

d) 2nd Aluminium layer 15 14 14 18 18 18

e) 3rd Aluminium layer 21 20 20 24 24 24

2.0 Raw Materials

2.1 Aluminium

a) Minimum purity of Aluminium % 99.50

b) Maximum copper content % 0.04

2.2 Steel wires/ rods

a) Carbon % 0.50 to 0.85

b) Manganese % 0.50 to 1.10


SECTION V VOL II

PAGE 2

c) Phosphorous % Not more than 0.035

Sl. Description Unit Standard Technical Particulars Conductors

ACSR

LAPWING

ACSR

BERSIMIS

ACSR

SNOWBIRD

ACSR

MOOSE

ACSR

ZEBRA

ACSR

BISON

d) Sulphur % Not more than 0.045

e) Silicon % 0.10 to 0.35 (Max.)

2.3 Zinc

a) Minimum purity of Zinc .% 99.95

3.0 Aluminum strands after stranding

3.1 Diameter

a) Nominal mm 4.78 4.57 3.99 3.53 3.18 3.00

b) Maximum mm 4.81 4.60 4.02 3.55 3.20 3.02

c) Minimum mm 4.75 4.54 3.96 3.51 3.16 2.98

3.2 Minimum breaking load of strand

a) Before stranding KN 2.87 2.64 2.12 1.57 1.29 1.17

b) After stranding KN 2.73 2.51 2.02 1.49 1.23 1.11

3.3 Max.resistance of 1 m length of strand at 20 deg. C Ohm 0.001595 0.001746 0.002295 0.002921 0.003604 0.004053

4.0 Steel strand after stranding

4.1 Diameter

a) Nominal mm 3.18 2.54 2.21 3.53 3.18 3.00

b) Maximum mm 3.24 2.59 2.25 3.59 3.24 3.06

c) Minimum mm 3.12 2.49 2.17 3.47 3.12 2.94

4.2 Minimum breaking load of strand

a) Before stranding KN 10.43 6.87 4.74 12.86 10.43 9.29


SECTION V VOL II

PAGE 3

b) After stranding KN 9.91 6.53 4.49 12.22 9.91 8.83

Sl. Description Standard Technical Particulars Conductors

ACSR

LAPWING

ACSR

BERSIMIS

ACSR

SNOWBIRD

ACSR

MOOSE

ACSR

ZEBRA

ACSR

BISON

4.3 Galvanising

a) Minimum weight of zinc coating per sq.m. gm 250 230 230 250 250 240

b) Minimum number of dips that the galvanised

strand can with stand in the standard preece test

Nos. 2 of one

minute & 1

of half

minute

2 of one minute 2 of one minute & 1 of half minute

c) Min. No. of twists in guage length equal 100 times

the dia. of wire which the strand can withstand in

the torsion test (after stranding)

Nos 16 16 16 16 16 16

5.0 Stranded Conductor

5.1 Overall diameter mm 38.22 35.04 30.57 31.77 28.62 27.00

5.2 Sectional area of Aluminium sq. mm 807.5 688.9 525.2 528.5 428.9 381.5

5.3 Total sectional area sq. mm 863.1 724.4 552.1 597.0 484.5 431

5.4 Minimum UTS of the conductor kN 188.0 154.0 118.0 161.20 130.32 117.5

5.5 Lay length of outer steel layer Max Min Max Min Max Min Max Min Max Min Max Min

a) 1st steel layer mm 30 18 24 16 24 16 18 16 18 13 18 16

b) 1st Aluminium layer mm 17 10 16 10 16 10 14 12 17 10 14 12

c) 2nd Aluminium layer mm 16 10 16 10 16 10 13 11 16 10 13 11

d) 3rd Aluminium layer mm 13 10 13 10 14 10 12 10 14 10 12 10

5.6 DC resistance of the conductor at 20°C ohm/km 0.0358 0.04242 0.05516 0.05552 0.06868 0.0758

5.7 Standard length of the conductor m 1800 2100 2100 2100 2200 2200


SECTION V VOL II

PAGE 4

5.8 Tolerance on Standard length % (+/-) 5

5.9 Direction of lay of outer layer Right Hand

Sl. Description Standard Technical Particulars Conductors

ACSR

LAPWING

ACSR

BERSIMIS

ACSR

SNOWBIRD

ACSR

MOOSE

ACSR

ZEBRA

ACSR

BISON

5.10 Linear mass of the conductor

a) Standard kg/km 2667 2181 1657 2004 1621 1444

b) Minimum kg/km 2628 2142 1632 1969 1589 1416

c) Maximum kg/km 2707 2221 1682 2040 1653 1473


SECTION V VOL II

PAGE 1

ANNEXURE-B

1. Tests on Conductor

1.1 D.C. Resistance Test on Stranded Conductor

On a conductor sample of minimum 5m length two contact-clamps shall be

fixed with a predetermined bolt torque. The resistance shall be measured by a

Kelvin double bridge or digital ohm-metre of sufficient accuracy by placing the

clamps initially zero metre and subsequently one metre apart. The test shall be

repeated at least five times and the average value recorded. The value obtained

shall be corrected to the value at 200C as per IS:398. The resistance corrected at

200C shall conform to the requirements indicated in the STP.

1.2 UTS Test on Stranded Conductor

Circles perpendicular to the axis of the conductor shall be marked at two places

on a sample of conductor of minimum 5 m length between fixing arrangement

suitably fixed on a tensile testing machine. The load shall be increased at a

steady rate upto 50% of minimum specified UTS and held for one minute. The

circles drawn shall not be distorted due to relative movement of strands.

Thereafter the load shall be increased at steady rate to 100% of the UTS of

conductor and held for one minute. The Conductor sample shall not fail during

this period. The applied load shall then be increased until the failing load is

reached and this value shall be recorded.

1.3 Corona Extinction Voltage Test

The sample assembly with each conductor of 5 m length shall be strung as per

the configuration shown in the Table below:

Line Configuration No of

conductors

per Bundle

Sub-

conductor

Spacing

(mm)

Maximum

Height of the

conductor

above ground

(m)

Minimum

Corona

extinction

voltage

(kV)

220 kV with Twin ACSR

BISON conductor

2 450 7 154

The sample assembly when subjected to power frequency/dc voltage under dry

condition shall have a corona extinction voltage of not less than the values

indicated in the table above. There shall be no evidence of corona on any part of

the samples. The test should be conducted without corona control rings.

However, small corona control rings may be used to prevent corona in the end

fittings. The atmospheric conditions during testing shall be recorded and test

results should be corrected for standard atmospheric conditions.


SECTION V VOL II

PAGE 2

1.4 Radio Interference Voltage Test

Under the conditions as specified under (1.2) above, the conductor samples

shall have radio interference voltage below 1000 microvolts. This test may be

carried out with corona control rings and arcing horns. The test procedure shall

be in accordance with IEC-60437.

1.5 Stress-Strain Test

Stress-strain test as per IEC-61089 latest edition shall be conducted keeping

conductor temperature at designed maximum temperature. UTS for this test

shall be as guaranteed in the GTP.

1.6 Visual and Dimensional Check on Drums

The drums shall be visually and dimensionally checked to ensure that they

conform to the requirements of this Specification.

1.7 Visual Check for Joints, Scratches etc. and length measurement of conductor by

rewinding

Conductor drums shall be rewound in the presence of the Employer. The Employer

shall visually check for scratches, joints etc. and that the conductor generally

conform to the requirements of this Specification. One drum out of ten drums or

part thereof from each lot shall be rewound in the presence of the Employer's

representative.

1.8 Measurement of diameters of individual Steel and Aluminium strands

The diameters of the individual strands shall be checked to ensure that they

conform to the requirement of this Specification.

1.9 Check for Lay-ratios of Various Layers

The lay-ratios of various layers shall be checked to ensure that they conform to the

requirements of this Specification.

1.10 Galvanizing Test

The test procedure shall be as specified in IEC 60888. The material shall conform to

the requirements of this Specification. The adherence of zinc shall be checked by

wrapping around a mandrel four times the diameter of steel wire.

1.11 Torsion and Elongation Tests on Steel Strands


SECTION V VOL II

PAGE 3

The test procedures shall be as per clause No. 10.3 of IEC 60888. In torsion test, the

number of complete twists before fracture shall not be less than that indicated in

the STP. In case test sample length is less or more than 100 times the stranded

diameter of the strand, the minimum number of twists will be proportioned to the

length and if number comes in the fraction then it will be rounded off to next

higher whole number. In elongation test, the elongation of the strand shall not be

less than 3.5% for a gauge length of 250 mm after stranding.

1.12 Procedure Qualification test on welded Aluminium

Two Aluminium wire shall be welded as per the standard quality plan and shall be

subjected to tensile load. The breaking strength of the welded joint of the wire shall

not be less than the breaking strength of individual strands.

1.13 Drum Strength Test of Steel drums

The details regarding Drum strength test will be discussed and mutually agreed to

by the supplier & Employer as per the Standard Quality Assurance Plan.

1.14 Barrel Batten Strength Test of Wooden Drums

The details regarding barrel batten strength test will be discussed and mutually

agreed to by the supplier & Employer as per the Standard Quality Assurance Plan.

1.15 Chemical Analysis of Zinc

Samples taken from the zinc ingots shall be chemically/ spectrographically

analyzed. The same shall be in conformity to the requirements stated in the

Specification.

1.16 Chemical Analysis of Aluminum

Samples taken from the aluminum ingots/rods shall be chemically/

spectrographically analyzed. The same shall be in conformity to the requirements

stated in the Specification.

1.17 Chemical Analysis of Steel

Samples taken from the steel rods shall be chemically/ spectrographically analyzed.

The same shall be in conformity to the requirements stated in the Specification.

SECTION-VIA


SECTION-VIA

CONTENTS

Clause No. Description Page No.

1.0 Technical Description of Composite Long Rod

Insulators

1

2.0 Equipment Marking 5

3.0 Bid Drawings 6

4.0 Tests and Standards 6

5.0 Annexure-A 14

6.0 Annexure-B 18


SECTION-VI A

VOLUME-II PAGE 1


SECTION-VIA

1.0 Technical Description of Composite Long Rod Insulators

1.1 Details of Composite Long Rod Insulators

1.1.1 The insulators of the strings shall consist of composite long rod insulators for a

three phase, 50 Hz, effectively earthed 220 kV kV AC transmission system

application in a very heavily polluted environment. Couplings shall be ball and

socket type.

1.1.2 Bidder shall quote such composite insulators which have proven use under

foggy/humid operational conditions in polluted industrial environment combined

with smoke and dust particles. The Bidder shall furnish evidence in the form of

certification from the power utilities that the similar type of product supplied to

them had been performing satisfactory. The Bidder shall also submit certified test

report for an accelerated ageing test of 5000 hours such as that described in

Appendix-C of IEC-61109.

1.1.3 Insulators shall have sheds of the ‚open aerodynamic profile without any under

ribs‛ with good self-cleaning properties. Insulator shed profile, spacing projection

etc. shall be strictly in accordance with the recommendation of IEC-60815.

1.1.4 The size of long rod insulator, minimum creepage distance, the number to be used

in different type of strings, their electromechanical strength and mechanical

strength of insulator string alongwith hardware fittings shall be as follows:

S.No Type of String *Size of

Composite

Insulator

(Core dia x

Nominal

length)

(mm)

Minimum

Creepage

Distance

(mm) per

unit

No. of

individual

Units per

String

(Nos.)

Electro-

Mechanical

Strength of

Insulator

Unit

(kN)

Mechanical

Strength of

Insulator String

along with

Hardware

Fittings

(kN)

FOR 220kV AC TRANSMISSION LINES WITH TWIN BISON CONDUCTOR

1. Single ‘I’ Suspension 20x2030 7595 1x1 70 70

2. Single Suspension

‘Pilot’ 20x2030

7595 1x1 70 70

3. Double Tension 20x2175 7595 2x1 120 2x120

Note: *The core dia of composite insulators mentioned at column No.3 is for indicative purpose.

The bidder shall offer composite long rod insulators of suitable core dia to meet specified

E&M and torsion strength requirements. For offered core dia, less than indicated in table

above, the bidder shall submit documentary evidence of past supplies & satisfactory

operation of the same for minimum period of three years. However, the overall string

length shall be within the limits specified in the drawing.


SECTION-VI A

VOLUME-II PAGE 2

1.2 Ball and Socket Designation

The dimensions of the Ball and Socket shall be of 16 mm (Alt-B) designation for 70

kN & 20mm designation for 120 kN Insulators in accordance with the standard

dimensions stated in IEC:60120/IS:2486 (Part-II).

1.3 Dimensional Tolerance of Composite Insulators

The tolerances on all dimensions e.g. diameter, length shall be allowed as follows:

± (0.04d+1.5) mm when d≤300 mm.

± (0.025d+6) mm when d>300 mm.

Where, d being the dimensions in millimeters for diameter, length as the case may

be.

The tolerance in creepage distance shall be based on design dimensions and their

tolerances. However, no negative tolerance shall be applicable to creepage

distance specified in clause 1.1.4.

1.4 Interchangeability

The composite long rod insulators inclusive of the ball & socket connection shall

be standard design suitable for use with the hardware fittings of any make

conforming to relevant IEC standards.

1.5 Corona and RI Performance

All surfaces shall be clean, smooth, without cuts, abrasions or projections. No part

shall be subjected to excessive localized pressure. The insulator and metal parts

shall be so designed and manufactured that it shall avoid local corona formation

and shall not generate any radio interference beyond specified limit under the

operating conditions.

1.6 Maintenance

1.6.1 The long rod insulators offered shall be suitable for employment of hot line

maintenance technique so that usual hot line operation can be carried out with

ease, speed and safety.

1.6.2 All insulators shall be designed to facilitate cleaning and insulators shall have the

minimum practical number of sheds and grooves. All grooves shall be so

proportioned that any dust deposit can be removed without difficulty either by

wiping with a cloth or by remote washing under live line condition.

1.7 Materials

1.7.1 Core

It shall be a glass-fiber reinforced (FRP rod) epoxy resin rod of high strength. The

rod shall be resistant to hydrolysis. Glass fibers and resin shall be optimized. The

rod shall be electrical grade corrosion resistant (ECR), boron free glass and shall

exhibit both high electrical integrity and high resistance to acid corrosion.


SECTION-VI A

VOLUME-II PAGE 3

1.7.2 Housing & Weathersheds

The FRP rod shall be covered by a sheath of a silicone rubber compound of a

thickness of minimum 3mm. The housing & weathersheds should have silicon

content of minimum 30% by weight. It should protect the FRP rod against

environmental influences, external pollution and humidity. It shall be extruded or

directly molded on the core. The interface between the housing and the core must

be uniform and without voids. The strength of the bond shall be greater than the

tearing strength of the polymer. The manufacturer shall follow non-destructive

technique (N.D.T.) to check the quality of jointing of the housing interface with the

core. The technique to be followed with detailed procedure and sampling shall be

furnished by the Supplier and finalized during finalization of MQP.

The weathersheds of the insulators shall be of alternate shed profile. The

weathersheds shall be vulcanized to the sheath (extrusion process) or molded as

part of the sheath (injection molding process) and free from imperfections. The

vulcanization for extrusion process shall be at high temperature and for injection

molding shall be at high temperature & high pressure. Any seams / burrs

protruding axially along the insulator, resulting from the injection molding

process shall be removed completely without causing any damage to the housing.

The track resistance of housing and shed material shall be class 1A 4.5 according

to IEC60587. The strength of the weathershed to sheath interface shall be greater

than the tearing strength of the polymer. The composite insulator shall be capable

of high pressure washing.

1.7.3 End Fittings

End fittings transmit the mechanical load to the core. They shall be made of

malleable cast iron spheroidal graphite or forged steel. They shall be connected to

the rod by means of a controlled compression technique. The manufacturer shall

have in-process Acoustic emission arrangement or some other arrangement to

ensure that there is no damage to the core during crimping. This verification shall

be in-process and done on each insulator. The system of attachment of end fitting

to the rod shall provide superior sealing performance between housing and metal

connection. The gap between fitting and sheath shall be sealed by a flexible

silicone rubber compound. The sealing shall stick to both housing and metal end

fitting. The sealing must be humidity proof and durable with time.

End fittings shall have suitable provisions for fixing grading rings at the correct

position as per design requirements.

1.7.4 Grading Rings

Grading rings shall be used at both ends of each composite insulator unit for

reducing the voltage gradient on and within the insulator and to reduce radio and

TV noise to acceptable levels. The size and placement of the metallic grading

rings shall be designed to eliminate dry band arcing/corona cutting/ exceeding of

permissible electrical stress of material. The insulator supplier shall furnish

design calculations using appropriate electric field software showing electric field

at surface of housing, inside housing & core and at the interface of housing and

metal fittings with the proposed placement and design of corona. Grading rings


SECTION-VI A

VOLUME-II PAGE 4

shall be capable of installation and removal with hot line tools without

disassembling any other part of the insulator assembly.

The design &supply of grading rings shall be in the scope of the composite

insulator supplier.

1.8 Workmanship

1.8.1 All the materials shall be of latest design and conform to the best modern practices

adopted in the extra high voltage field. Bidders shall offer only such insulators as

are guaranteed by him to be satisfactory and suitable for transmission lines

specified and will give continued good service.

1.8.2 The design, manufacturing process and material control at various stages shall be

such as to give maximum working load, highest mobility, best resistance to

corrosion, good finish and elimination of sharp edges and corners to limit corona

and radio interference.

1.8.3 The design of the insulators shall be such that stresses due to expansion and

contraction in any part of the insulator shall not lead to deterioration.

1.8.4 The core shall be sound and free of cracks, impurities and voids that may

adversely affect the insulators.

1.8.5 Weather sheds/ Housing shall be uniform in quality. It shall be free from voids

and impurities. Weather sheds/Housing shall be clean, sound, smooth and free

from gross defects and excessive flashing at parting lines.

1.8.6 End fittings shall be free from cracks, seams, shrinks, air holes and rough edges.

End fittings should be effectively, sealed to prevent moisture ingress, effectiveness

of sealing system must be supported by test documents. All surfaces of the metal

parts shall be perfectly smooth with the projecting points or irregularities which

may cause corona. All load bearing surfaces shall be smooth and uniform so as to

distribute the loading stresses uniformly.

1.8.7 All ferrous parts shall be hot dip galvanized to give a minimum average coating of

zinc equivalent to 600 gm/sq.m. and shall be in accordance with the requirement

of ISO:1461 (E) and shall satisfy the tests mentioned in ISO:1460 (E). The zinc used

for galvanizing shall be of purity of 99.95%. The zinc coating shall be uniform,

adherent, smooth, reasonably bright continuous and free from imperfections such

as flux, ash rust stains, bulky white deposits and blisters. The galvanized metal

parts shall be guaranteed to withstand at least six successive dips each lasting for

one (1) minute duration under the standard preece test. The galvanizing shall be

carried out only after any machining.

1.8.8 The supplier shall guarantee that there shall not be any failure/ decapping /

breaking of insulators on line under normal operating condition. In the event of

any failure/ decapping /breaking of insulators during the first ten years of service,

Supplier shall supply to the owner free of cost spare insulators equal to 10 times

the failed insulator quantity. Further, in case of decapping / Breaking and

subsequent line drop, during the first ten years of service, the supplier shall also

have to pay Rs 1,00,000/- (Rs one lakh only) per dropped string towards

expenditure to be incurred by NEA for this line repair


SECTION-VI A

VOLUME-II PAGE 5

2.0 Equipment Marking

2.1 Each composite long rod unit shall be legibly and indelibly marked with the trade

mark of the manufacturer, name of NEA and month & year of manufacture. The

guaranteed combined mechanical and electrical strength shall be indicated in kilo

Newton followed by the word ‘kN’ to facilitate easy identification and to ensure

proper use.

2.2 One 10 mm thick ring or 20 mm thick spot of suitable quality of paint shall be

marked on the cap/end fitting of each composite long rod of particular strength

for easy identification of the type of insulator. The paint shall not have any

deteriorating effect on the insulator performance. Following codes shall be used as

identification mark:

For 70 kN long rod unit : Black

For 120 kN long rod unit : Yellow

3.0 Bid Drawings

3.1 The Bidder shall furnish full description and illustration of the material offered.

3.2 The Bidder shall furnish along with the bid the outline drawing of each insulator

unit along with grading rings including a cross sectional view of the long rod

insulator unit. The drawing shall include but not limited to the following

information:

(a) Major Dimensions with manufacturing tolerances

(b) Minimum Creepage distance with positive tolerance

(c) Protected creepage distance

(d) Unit mechanical and electrical characteristics

(e) Size and weight of ball and socket parts

(f) Weight of composite long rod units

(g) Materials

3.3 After placement of award, the Supplier shall submit full dimensioned insulator

drawings containing all the details as given in Clause No. 3.2 above, in four (4)

copies to Owner for approval. After getting approval from Owner, the Supplier

shall submit 10 more copies of the same drawing along with a soft copyto the

Owner for further distribution and field use at Owner's end.

3.4 After placement of award the Supplier shall also submit fully dimensioned

insulator crate drawing for different type of insulators.


4.1 Type Tests

The required type tests on composite longrod units, components, materials and

complete strings are stipulated hereunder.


SECTION-VI A

VOLUME-II PAGE 6

The specified type tests under the following clause shall not be required to be

carried out if a valid test certificate is available for a similar design. The tests

certificate shall be considered valid if:

i. Tests conducted earlier is either conducted in accredited laboratory


accreditation body of the country where laboratory is located) or witnessed by

the representative(s) of any utility and

ii. Tests have been conducted not prior to 5 (five) years from the date of bid

opening.

In case the test have been conducted earlier than the above stipulated period or in

the event of any discrepancy in the test report (i.e., any test not applicable due to

any design/manufacturing change including substitution of components or due to

non-compliance with the requirement stipulated in the Technical Specifications),

the tests shall be conducted by the Supplier at no extra cost to the Purchaser.

4.1.1 On the complete composite Long Rod Insulator String with Hardware Fittings

Test Ref Strings on which test to be

conducted

(a) Power frequency voltage withstand

test with corona control

rings/grading ring and arcing horns

under wet condition

IEC:383-

1993/ Annex-

A SISP, SI, DT

(b) Switching surge voltage withstand

test under wet condition

IEC:383-1993

SISP, SI, DT

(c) Impulse voltage withstand test

under dry condition

IEC:383-1993

SISP, SI, DT

(d) Corona and RIV test under dry

condition

Anex-A SISP, SI, DT

(e) Mechanical Strength test Anex-A SISP, SI, DT

(f) Vibration test Anex-A SI, DT

(g) Salt-fog pollution withstand test Anex-A

SI :Single I Suspension ; SISP :Single I Suspension Pilot ; DT :Double Tension

4.1.2 On Composite Insulator Units

(a) (a) Tests on interfaces and connections of metal fittings IEC: 61109-2008

(b) Assembled core load time test IEC: 61109-2008

(c) Damage limit proof test and test of tightness of

interface between end fittings and insulator housing.

IEC: 61109-2008


SECTION-VI A

VOLUME-II PAGE 7

(d) High Pressure washing test Annexure-A

(e) Brittle fracture resistance test Annexure-A

(f) Dye penetration test IEC: 61109-2008

(g) Water diffusion test IEC: 61109-2008

(h) Tracking and erosion test IEC: 61109-2008

(i) Hardness test IEC: 61109-2008

(j) Accelerated weathering test IEC: 61109-2008

(k) Flammability test IEC: 61109-2008

(l) Silicone content test Annexure-A

(m) Recovery of Hydrophobicity test Annexure-A

(n) Torsion test Annexure-A

Hardness test, Accelerated weathering test & Flammability test specified under

Clause No.4.1.2 above shall be conducted on housing/ weathershed of either 70kN

or 120kN composite long rod for the same type of material.

4.2 Acceptance Tests:

4.2.1 For Composite Long Rod Insulators

a) Verification of dimensions IEC : 61109-2008

b) Galvanising test IEC : 60383

c) Verification of end fittings IEC: 61109 -2008

d) Recovery of Hydrophobicity Annexure-A

e) Verification of tightness of interface between end

fittings and insulator housing and of specified

mechanical load

IEC : 61109-2008

f) Tests on interfaces and connections of metal

fittings IEC: 61109-2008

g) Silicone content test Annexure-A

h) Brittle Fracture Resistance Test Annexure-A

i) Dye Penetration Test IEC :61109-2008

j) Water Diffusion Test IEC : 61109-2008

The test 4.2.1.(f) to (j) shall be carried out as acceptance test on any one lot.

In the event of failure of the sample to satisfy the acceptance test(s) specified in 4.2

above, the retest procedure shall be as per IEC 61109.


SECTION-VI A

VOLUME-II PAGE 8

4.3 Routine Tests

4.3.1 For Composite Long Rod Insulator Units

a) Visual Examination As per IEC:61109-2008

b) Mechanical routine test As per IEC:61109 -2008

4.4 Tests During Manufacture

On all components as applicable

a) Chemical analysis of zinc used for galvanising As per Annexure-A

b) Chemical analysis, mechanical, metallographic

test and magnetic particle inspection for

malleable castings.

As per Annexure-A

c) Chemical analysis hardness tests and magnetic

particle inspection for forgings As per Annexure-A

d) Tracking and erosion test on insulating

material IEC 60587


4.5.1 As mentioned under clause 4.1 above, no type test charges shall be payable to the

supplier.

4.5.2 For Type Tests which involves the tests on the complete insulator string with

hardware fitting, standard hardware fittings similar to existing insulator strings

shall be arranged and used by the insulator supplier at his own cost.

4.5.3 In case of failure in any type test the supplier is either required to modify the

design of the material & successfully carryout all the type tests as has been

detailed out in Clause 4.1 of this specifications or to repeat that particular type test

at least three times successfully at his own expenses.

4.5.4 Bidder shall indicate the laboratories in which they propose to conduct the type

tests. They shall ensure that adequate facilities are available in the laboratory and

the tests can be completed in these laboratories within the time schedule

guaranteed by them in the appropriate schedule.

4.5.5 The entire cost of testing for acceptance and routine tests and tests during

manufacture specified herein shall be treated as included in the quoted Ex-

works/CIF Price.

4.5.6 In case of failure in any type test, if repeat type tests are required to be conducted,

then all the expenses for deputation of Inspector/ Owner's representative shall be

deducted from the contract price. Also if on receipt of the Supplier's notice of

testing, the Owner's representative does not find the material or test setup /


SECTION-VI A

VOLUME-II PAGE 9

equipments to be ready for testing, the expenses incurred by the Owner for re-

deputation shall be deducted from contract price.

4.5.7 The Supplier shall intimate the Owner about carrying out of the type tests

alongwith detailed testing programme at least 3 weeks in advance (in case of

domestic testing) and at least 6 weeks advance (in case of testing abroad) of the

scheduled date of testing during which the Owner will arrange to depute his

representative to be present at the time of carrying out the tests.

4.6 Sample Batch for Type Testing

4.6.1 The Supplier shall offer material for sample selection for type testing only after

getting Quality Assurance Programme approved by the Owner. The Supplier shall

offer at least three times the quantity of materials required for conducting all the

type tests for sample selection. The sample for type testing will be manufactured

strictly in accordance with the Quality Assurance Programme approved by the

Owner.

4.6.2 Before sample selection for type testing, the Supplier shall be required to conduct

all the acceptance tests successfully in presence of Owner's representative.

4.7 Schedule of Testing

4.7.1 The Bidder has to indicate the schedule of following activities in their bids :

a) Submission of drawing for approval.

b) Submission of Quality Assurance Programme for approval.

c) Offering of material for sample selection for type tests.

d) Type testing.


4.8.1 The Owner reserves the right of having at his own expenses any other test(s) of

reasonable nature carried out at Supplier's premises, at site, or in any other place

in addition to the aforesaid type, acceptance and routine tests to satisfy himself

that the material comply with the Specifications.

4.8.2 The Owner also reserves the right to conduct all the tests mentioned in this

specification at his own expense on the samples drawn from the site at Supplier's

premises or at any other test centre. In case of evidence of non compliance, it shall

be binding on the part of the Supplier to prove the compliance of the items to the

technical specifications by repeat tests or correction of deficiencies or replacement

of defective items, all without any extra cost to the Owner.

4.9 Guarantee

The Supplier of insulators shall guarantee overall satisfactory performance of the

insulators.


SECTION-VI A

VOLUME-II PAGE 10

4.10 Test Reports

4.10.1 Copies of type test reports shall be furnished in at least six (6) copies alongwith

one original. One copy shall be returned duly certified by the Owner only after

which the commercial production of the concerned material shall start.

4.10.2 Copies of acceptance test reports shall be furnished in at least six (6) copies. One

copy shall be returned duly certified by the Owner, only after which the material

shall be dispatched.

4.10.3 Record of routine test reports shall be maintained by the Supplier at his works for

periodic inspection by the Owner’s representative.

4.10.4 Test certificates of test during manufacture shall be maintained by the Supplier.

These shall be produced for verification as and when desired by the Owner.

4.11 Inspection

4.11.1 The Owner’s representative shall at all times be entitled to have access to the

works and all places of manufacture, where insulator, and its component parts

shall be manufactured and the representatives shall have full facilities for

unrestricted inspection of the Supplier’s and sub-Supplier’s works, raw materials,

manufacture of the material and for conducting necessary test as detailed herein.

4.11.2 The material for final inspection shall be offered by the Supplier only under

packed condition as detailed in clause No.4.12 of the specification. The Owner

shall select samples at random from the packed lot for carrying out acceptance

tests. The lot should be homogeneous and should contain insulators

manufactured in 3-4 consecutive weeks.

4.11.3 The Supplier shall keep the Owner informed in advance of the time of starting and

the progress of manufacture of material in their various stages so that

arrangements could be made for inspection.

4.11.4 No material shall be dispatched from its point of manufacture before it has been

satisfactorily inspected and tested unless the inspection is waived off by the

Owner in writing. In the latter case also the material shall be dispatched only after

satisfactory testing for all tests specified herein have been completed.

4.11.5 The acceptance of any quantity of material shall be no way relieve the Supplier of

his responsibility for meeting all the requirements of the specification and shall

not prevent subsequent rejection, if such material are later found to be defective.

4.12 Packing and Marking

4.12.1 All insulators shall be packed in suitable PVC/ plastic tubes/any other suitable

packing. The packing shall provide protection against rodent. The Supplier shall

furnish detailed design of the packing. For marine transportation, crates shall be

palleted.

4.12.2 The packing shall be of sufficient strength to withstand rough handling during

transit, storage at site and subsequent handling in the field.


SECTION-VI A

VOLUME-II PAGE 11

4.12.3 Suitable cushioning, protective padding, or dunnage or spacers shall be provided

to prevent damage or deformation during transit and handling.

4.12.4 All packing cases shall be marked legibly and correctly so as to ensure safe arrival

at their destination and to avoid the possibility of goods being lost or wrongly

dispatched on account of faulty packing and faulty or illegible markings. Each

case/crate shall have all the markings stenciled on it in

4.12.5 The Supplier shall guarantee the adequacy of the packing and shall be responsible

for any loss or damage during transportation, handling, storage and installation

due to improper packing. indelible ink.

4.13 Standards

The insulator strings and its components shall conform to the following

Standards which shall mean latest revision, with amendments/

changes adopted and published, unless specifically stated otherwise in the

Specification.

4.13.1 In the event of supply of insulators conforming to standards other than specified,

the Bidder shall confirm in his bid that these standards are equivalent or better to

those specified. In case of award, salient features of comparison between the

standards proposed by the Bidder and those specified in this document will be

provided by the Supplier to establish equivalence.

Sl. No. Indian Standard Title International Standard

1. IS:209-1992 Specification for zinc BS:3436

2. IS:406-1991 Method of Chemical Analysis of Slab Zinc BS:3436

3. IS:731-1991 Porcelain insulators for overhead Power lines

with a nominal voltage greater than 1000 V

BS:137- (I&II)

IEC:60383

4. IS:2071 Part (I) –

1993 (Part(II)- 1991

Part(III)- 1991

Methods of High Voltage Testing IEC:60060-1

5. IS:2486

Part- I-1993

Part- II-1989

Part-III-1991

Specification for Insulator fittings for Overhead

Power Lines with a nominal voltage greater

than 1000V

General Requirements and Tests

Dimensional Requirements

Locking Devices

BS:3288

IEC:60120

IEC:60372

6. IS:2629-1990 Recommended Practice for Hot, Dip

Galvanisation for iron and steel

ISO-1461 (E)

7. IS:2633-1992 Testing of Uniformity of Coating of zinc coated

articles

8. IS:6745-1990 Determination of Weight of Zinc Coating on

Zinc coated iron and steel articles

BS:433-1969 ISO:1460-

1973


SECTION-VI A

VOLUME-II PAGE 12

Sl. No. Indian Standard Title International Standard

9. IS:8263-1990 Methods of RI Test of HV insulators IEC:60437

NEMAPubli- cation

No.07/ 1964/ CISPR

10. IS:8269-1990 Methods for Switching Impulse test on HV

insulators

IEC:60506

11. Thermal Mechanical Performance test and

mechanical performance test on string insulator

units

IEC: 60575

12. Salt Fog Pollution Voltage Withstand Test IEC:60507

13. Composite insulators for A.C. Overhead lines

with nominal voltage greater than 1000V –

Definitions, test methods and acceptance criteria

IEC 61109

14. Selection and dimensioning of high voltage

insulators intended for use in polluted

conditions: Polymer Insulators for AC systems

IEC:60815-3

15. Tests on insulators of Ceramic material or glass

or glass for overhead lines with a nominal

voltage greater than 1000V

IEC:60383

16. Composite string insulator units for overhead

lines with a nominal voltage above 1000V :

Standard strength classes and end fittings

IEC 61466-1

17. Composite string insulator units for overhead

lines with a nominal voltage above 1000V :

Dimensional and electrical characteristics

IEC 61466-2

18 Electrical Insulating materials used under severe

ambient conditions –Test methods for

evaluating resistance to tracking and erosion

IEC 60587

19 Polymeric insulators for indoor and outdoor use

with nominal voltage greater than 1000V-

General definitions, tests, methods and

acceptance criteria.

IEC 62217


Reference Abbreviation Name and Address

BS British Standards, British Standards Institution 101, Pentonvile Road, N - 19-ND, UK




1 Rue de verembe,

Geneva, SWITZERLAND

BIS/IS Beureau Of Indian Standards.

ManakBhavan,

9, Bahadur Shah ZafarMarg,


SECTION-VI A

VOLUME-II PAGE 13

New Delhi - 110001.INDIA

ISO International Organisation for Standardization.



Aurehoegvej-12

DK-2900, Heeleprup, DENMARK



New York, NY 10017U.S.A.

ASTM American Society for Testing and Materials,

1916 Race St. Philadelphia, PA19103 USA


SECTION-VI A

VOLUME-II PAGE 14

ANNEXURE-A

1.0 Tests on Complete Strings with Hardware Fittings

1.1 Corona Extinction Voltage Test (Dry)

The sample assembly when subjected to power frequency voltage shall have a

corona extinction voltage of not less than 154 kV (rms) line to ground under dry

condition under dry condition. There shall be no evidence of corona on any part of

the sample. The atmospheric condition during testing shall be recorded and the

test results shall be accordingly corrected with suitable correction factor as

stipulated in IEC : 60383.

1.2 RIV Test (Dry)

Under the conditions as specified under (1.1) above, the insulator string along

with complete hardware fittings shall have a radio interference voltage level

below 1000 micro volts at one MHz when subjected to 50 Hz AC voltage of 154 kV

line to ground under dry condition. The test procedure shall be in accordance

with IS: 8263/ IEC: 60437.

1.3 Mechanical Strength Test

Mechanical Strength Test for insulator strings for 220 kV line

The complete insulator string along with its hardware fitting excluding arcing

horn, corona control ring, grading ring and suspension assembly/dead end

assembly shall be subjected to a load equal to 50% of the specified minimum

ultimate tensile strength (UTS) which shall be increased at a steady rate to 67% of

the minimum UTS specified. The load shall be held for five minutes and then

removed. After removal of the load, the string components shall not show any

visual deformation and it shall be possible to disassemble them by hand. Hand

tools may be used to, remove cotter pins and loosen the nuts initially. The string

shall then be reassembled and loaded to 50% of UTS and the load shall be further

increased at a steady rate till the specified minimum UTS and held for one minute.

No fracture should occur during this period. The applied load shall then be

increased until the failing load is reached and the value recorded.

1.4 Vibration Test

The suspension string shall be tested in suspension mode, and tension string in

tension mode itself in laboratory span of minimum 30 meters. In the case of

suspension string, a load equal to 600 kg shall be applied along the axis of the

suspension string by means of turn buckle. The insulator string along with

hardware fittings and the each sub-conductors tensioned at 25% of conductor UTS

shall be secured with clamps. The system shall be suitable to maintain constant

tension on each sub-conductors throughout the duration of the test. Vibration

dampers shall not be used on the test span. All the sub-conductors shall be

vertically vibrated simultaneously at one of the resonance frequencies of the

insulators string (more than 10 Hz) by means of vibration inducing equipment.

The peak to peak displacement in mm of vibration at the antinode point, nearest

to the string, shall be measured and the same shall not be less than 1000/f1.8 where


SECTION-VI A

VOLUME-II PAGE 15

f is the frequency of vibration in cycles/sec. The insulator string shall be vibrated

for not less than 10 million cycles without any failure. After the test, the insulators

shall be examined for looseness of pins and cap or any crack. The hardware shall

be examined for looseness, fatigue failure and mechanical strength test. There

shall be no deterioration of properties of hardware components and insulators

after the vibration test. The insulators shall be subjected to the Mechanical

performance test followed by mechanical strength test as per relevant standards.

1.5 Salt-fog pollution withstand test

This test shall be carried out in accordance with IEC:60507. The salinity level for

composite long rod insulators shall be 160Kg/m3 NaCl.

2.0 Composite Longrod Insulator Units

2.1 Brittle Fracture Resistance Test

The test arrangement shall be according to Damage limit proof test with

simultaneous application of 1N-HNO3 acid directly in contact with naked FRP

rod. The contact length of acid shall not be less than 40mm and thickness around

the core not less than 10mm.The rod shall withstand 80% of SML for 96 hours.

2.2 Recovery of Hydrophobicity Test

(1) The surface of selected samples shall be cleaned with isopropyl alcohol.

Allow the surface to dry and spray with water. Record the HC classification.

Dry the sample surface.

(2) Treat the surface with corona discharges to destroy the hydrophobicity. This

can be done utilizing a high frequency corona tester, Holding the electrode

approximately 3mm from the sample surface, slowly move the electrode over

an area approximately 1‛ x 1‛. Continue treating this area for 2 – 3 minutes,

operating the tester at maximum output.

(3) Immediately after the corona treatment, spray the surface with water and

record the HC classification. The surface should be hydrophilic, with an HC

value of 6 or 7. If not, dry the surface and repeat the corona treatment for a

longer time until an HC of 6 or 7 is obtained. Dry the sample surface.

(4) Allow the sample to recover and repeat the hydrophobicity measurement at

several time intervals. Silicone rubber should recover to HC 1 – HC 2 within

24 to 48 hours, depending on the material and the intensity of the corona

treatment.

2.3 Silicone content test

Minimum content of silicone as guaranteed by supplier shall be verified through

FT-IR spectroscopy & TGA analysis or any other suitable method mutually agreed

between Owner& Supplier in Quality Assurance Programme.

2.4 High Pressure washing test

The washing of a complete insulator of each E&M rating is to be carried out at

3800kPa with nozzles of 6mm diameter at a distance of 3m from nozzles to the

insulator, The washing shall be carried out for 10minutes. There shall be no


SECTION-VI A

VOLUME-II PAGE 16

damage to the sheath or metal fitting to housing interface. The verification shall be

1 minute wet power frequency withstand test at 460kV r.m.s.

2.5 Torsion Test

Three complete insulators of each E&M rating shall be subjected to a torsional

load of 55Nm. The torsional strength test shall be made with test specimen

adequately secured to the testing machine. The torsional load shall be applied to

the test specimen through a torque member so constructed that the test specimen

is not subjected to any cantilever stress. The insulator after torsion test must pass

the Dye Penetration Test as per IEC 61109.

3.0 Tests on All components (As applicable)

3.1 Chemical Analysis of Zinc used for Galvanizing

Samples taken from the zinc ingot shall be chemically analysed as

per IS:209-1979. The purity of zinc shall not be less than 99.95%.

3.2 Tests for Forgings

The chemical analysis hardness tests and magnetic particle inspection for forgings,

will be as per the internationally recognized procedures for these tests. The

sampling will be based on heat number and heat treatment batch. The details

regarding test will be as discussed and mutually agreed to by the Supplier and

Owner in Quality Assurance Programme.

3.3 Tests on Castings

The chemical analysis, mechanical and metallographic tests and magnetic, particle

inspection for castings will be as per the internationally recognized procedures for

these tests. The samplings will be based on heat number and heat treatment batch.

The details regarding test will be as discussed and mutually agreed to by the

Supplier and Owner in Quality Assurance Programme.


SECTION-VII


SECTION-VII

CONTENTS

Clause Description Page

No.

1.0 Technical Description of Hardware Fittings 1

2.0 Technical Description of Accessories for Conductor 11

3.0 Technical Description of Accessories for 7/3.35 mm GS Earthwire 21

4.0 Type Tests & Standards 35

Annexure-A 46

Annexure-B 56


SECTION–VII, VOLUME-II PAGE-

1


SECTION - VII

1.0 Technical Description of Hardware Fittings

1.1 General

This section details technical particulars of hardware fittings and accessories

suitable for twin ACSR BISON Conductor to be supplied by the bidder.

The hardware fittings shall be suitable for use with Disc insulators and /or

composite long rod insulators having ball and socket fittings. The hardware

fittings shall be as per the specification drawings enclosed in the section of

drawings of the specification. Each hardware fitting shall be supplied

complete in all respects and shall include the following hardware parts:

1.1.1 Suitable arcing horn as specified in clause 1.8 hereinafter.

1.1.2 Suitable yoke plates complying with the specifications given hereinafter.

1.1.3 Corona control rings/grading ring with fittings for attachment to line side

yoke plate.

1.1.4 Sag adjustment plate for Double / Quad tension hardware fittings and turn

buckle for single tension hardware fittings.

1.1.5 Suspension and dead end assembly to suit conductor size as detailed in

clause 1.13, 1.14 and 1.15 hereinafter.

1.1.6 Provisions for attaching balancing weights on the line side yoke plate of

single suspension pilot hardware fittings.

1.1.7 Other necessary fittings viz D-shackles, eye links, extension links, ball

clevis, socket clevis, clevis eye, U clevis and chain link etc. to make the

hardware fittings complete.

1.1.8 2.5% extra fasteners.

1.2 Dimensions of Insulator String Along with Hardware Fitting

The various limiting dimensions of the insulator strings shall generally be in

conformity with the dimensions of the existing hardware fittings. The

Contractor shall be required to verify the dimensions of the existing

insulator strings and shall ensure that the new fittings are generally

conforming to the dimensions of the existing fittings.



2

1.3 Interchangeability

1.3.1 The hardware for insulator strings with composite/ disc insulators together

with ball and socket fittings shall be of standard design, so that these

hardware are interchangeable with each other and suitable for use with

insulators of any make conforming to relevant Standards.

1.4 Corona and RI Performance

Sharp edges and scratches on all the hardware fittings shall be avoided. All

surfaces must be clean, smooth, without cuts and abrasions or projections.

The Contractor must give suitable assurance about the satisfactory corona

and radio interference performance of the materials offered by him.

1.5 Maintenance

1.5.1 The hardware fittings offered shall be suitable for employment of hot line

maintenance technique so that usual hot line operations can be carried out

with ease, speed and safety. The technique adopted for hot line maintenance

shall be generally bare hand method & hot stick method.

1.5.2 The line side yoke plate shall have a notch & a working hole of suitable size.

The design of corona control rings/grading ring shall be such that it can be

easily replaced by employing hot line maintenance technique.

1.6 Designation

1.6.1 Ball and Socket Designation

The dimensions of the ball and socket are furnished in section-I of this

specification. The designation should be in accordance with the standard

dimensions stated in IS:2486-(Part-II)/IEC:60120. The dimensions shall be

checked by the appropriate gauge after galvanising only.

1.7 Security Clips and Split Pins

1.7.1 Security clips for use with ball and socket coupling shall be R-shaped, hump

type which provides positive locking of the coupling as per IS:2486-(Part-

III)/ IEC : 60372. The legs of the security clips shall be spread after assembly

in the works to prevent complete withdrawal from the socket. The locking

device should be resilient, corrosion resistant and of suitable mechanical

strength. There shall be no risk of the locking device being displaced

accidentally or being rotated when in position. Under no circumstances shall

the locking devices allow, separation of fittings.



3

1.7.2 The hole for the security clip shall be countersunk and the clip should be of

such design that the eye of clip may be engaged by a hot line clip puller to

provide for disengagement under energised conditions. The force required

to pull the security clip into its unlocked position shall not be less than 50 N

(5 kg) or more than 500 N (50 kg).

1.7.3 Split pins shall be used with bolts & nuts.

1.8 Arcing Horn/Intermediate Arcing Horn

1.8.1 The arcing horn / Intermediate Arcing Horn shall be either ball ended rod

type or tubular type.

1.8.2 The arcing horn shall be provided as shown on the drawing of the hardware

fittings, in this specification.

1.8.3 The air gap shall be so adjusted to ensure effective operation under actual

field conditions.

1.9 Yoke Plates

The strength of yoke plates shall be adequate to withstand the minimum

ultimate tensile strength as specified in the bid drawings.

The plates shall be either triangular or rectangular in shape as may be

necessary. The design of yoke plate shall take into account the most

unfavorable loading conditions likely to be experienced as a result of

dimensional tolerances for disc insulators as well as components of

hardware fittings within the specified range. The plates shall have suitable

holes for fixing corona control rings/grading ring/arcing horn. All the

corners and edges should be rounded off with a radius of atleast 3 mm.

Design calculations i.e. for bearing & tensile strength, for deciding the

dimensions of yoke plate shall be furnished by the contractor. The holes

provided for bolts in the yoke plate should satisfy shear edge condition as

per relevant clause of IS:800-2007.

1.10 Corona Control Rings/Grading Ring

1.10.1 The Corona control rings/ grading ring shall be provided with hardware

fittings. It shall also improve corona and radio interference performance of

the complete insulator string along with hardware fittings.

1.10.2 The corona control rings/grading ring shall be made of high strength heat

treated aluminium alloy tube of minimum 2.5 mm wall thickness. If mild

steel brackets are used then the brackets shall not be welded to the pipe but

shall be fixed by means of bolts and nuts on a small aluminium plate

attachment welded to the pipe. The welded center of the corona control

ring/grading ring shall be grinded before buffing. Alternately, Aluminium



4

tube/flats of suitable dimensions welded to the corona control rings/grading

rings may be used for connection to yoke plate.

1.10.3 The Corona control rings/grading ring should have a brushed satin finish

and not a bright glossy surface. No blemish should be seen or felt when

rubbing a hand over the metal.

1.10.4 The limiting dimensions of corona control ring shall be as per the

specification drawings.

1.10.5 Bidder may quote for grading ring with armour grip suspension assembly.

The grading ring shall be of open type design with a gap of 125 mm. The

open ends shall be suitably terminated. The outside diameter of the tube

shall be 60 mm. The ends of grading ring tube shall be sealed with welded

aluminum cap duly buffed.

1.11 Sag Adjustment Plate

1.11.1 The sag-adjustment plate to be provided with the quadruple/double tension

hardware fitting shall be of three plate type. The sag adjustment plate shall

be provided with a safety locking arrangement. The device shall be of such

design that the adjustment is done with ease, speed and safety.

1.11.2 The maximum length of the sag adjustment plate from the connecting part

of the rest of the hardware fittings shall be 520 mm. The details of the

minimum and maximum adjustment possible and the steps of adjustment

shall be clearly indicated in the drawing. An adjustment of 150 mm

minimum at the interval of 6 mm shall be possible with the sag adjustment

plate.

1.11.3 Design calculations for deciding the dimensions of sag adjustment plate

shall be furnished by Contractor. The hole provided for bolts should satisfy

shear edge condition as per relevant clause of IS:800-2007.

1.12 Turn Buckle

1.12.1 The turn buckle is to be provided with single tension hardware fitting. The

threads shall be of sufficient strength to remain unaffected under the

specified tensile load.

1.12.2 The maximum length of the turn buckle from the connecting part of the rest

of the hardware fittings shall be 520 mm. The details of the minimum and

maximum adjustment possible shall be clearly indicated in the drawing. An

adjustment of 150 mm minimum shall be possible with turn buckle.

1.13 Suspension Assembly



5

1.13.1 The suspension assembly shall be suitable for the specific conductor as given

in Section – I of this Specification.

1.13.2 The suspension assembly shall include free center type suspension clamp

along with standard preformed armour rods or armour grip suspension

clamp; except for Pilot insulator string for which only suitable Envelope

type suspension clamp shall be used.

1.13.3 The suspension clamp along with standard preformed armour rods set shall

be designed to have maximum mobility in any direction and minimum

moment of inertia so as to have minimum stress on the conductor in the case

of oscillation of the same.

1.13.4 The suspension clamp along with standard preformed armour rods/armour

grip suspension clamp set shall have the slip strength not less than that

specified in the Standard Technical Particulars.

1.13.5 The suspension assembly shall be designed, manufactured and finished to

give it a suitable shape, so as to avoid any possibility of hammering between

suspension assembly and conductor due to vibration. The suspension

assembly shall be smooth without any cuts, grooves, abrasions, projections,

ridges or excrescence, which might damage the conductor.

1.13.6 The suspension assembly/clamp shall be designed so that it shall minimise

the static & dynamic stress developed in the conductor under various

loading conditions as well as during wind induced conductor vibrations. It

shall also withstand power arcs & have required level of Corona/RIV

performance.

1.13.7 The magnetic power loss shall not be more than that stipulated in the

Standard Technical Particulars.

1.13.8 Free Center Type Suspension Clamp

For the Free Center Suspension Clamp seat shall be smoothly rounded and

curved into a bell mouth at the ends. The lip edges shall have rounded bead.

There shall be at least two U-bolts for tightening of clamp body and keeper

pieces together.

1.13.10 Standard Preformed Armour Rod Set

1.13.10.1 The Preformed Armour Rods Set, suitable for specific Conductor, shall be

used to minimise the stress developed in the sub-conductor due to different

static and dynamic loads because of vibration due to wind, slipping of

conductor from the suspension clamp as a result of unbalanced conductor

tension in adjacent spans and broken wire condition. It shall also withstand

power arcs, chafing and abrasion from suspension clamp and localised



6

heating effect due to magnetic power losses from suspension clamps as well

as resistance losses of the conductor.

1.13.10.2 The preformed armour rods set shall have right hand lay and the inside

diameter of the helics shall be less than the outside diameter of the

conductor to have gentle but permanent grip on the conductor. The surface

of the armour rod when fitted on the conductor shall be smooth and free

from projections, cuts and abrasions etc.

1.13.10.3 The pitch length of the rods shall be determined by the Contractor but shall

be less than that of the outer layer of conductor and the same shall be

accurately controlled to maintain uniformity and consistently reproducible

characteristic wholly independent of the skill of linemen.

1.13.10.4 The length of each rod along with permissible tolerances shall be as

stipulated in the Standard Technical Particulars. The end of armour rod shall

be parrot billed.

1.13.10.5 The number of armour rods in each set shall as stipulated in the Standard

Technical Particulars. Each rod shall be marked in the middle with paint for

easy application on the line.

1.13.10.6 The armour rod shall not loose their resilience even after five applications.

1.13.10.7 The conductivity of each rod of the set shall not be less than 40% of the

conductivity of the International Annealed Copper Standard (IACS).

1.13.11 Armour Grip Suspension Clamp

1.13.11.1 The armour grip suspension clamp shall comprise of retaining strap,

support housing, elastomer inserts with aluminium reinforcements and AGS

preformed rod set.

1.13.11.2 Elastomer insert shall be resistant to the effects of temperature up to 95oC,

Ozone, ultraviolet radiations and other atmospheric contaminants likely to

be encountered in service. The physical properties of the elastomer shall be

of approved standard. It shall be electrically shielded by a cage of AGS

performed rod set. The elastomer insert shall be so designed that the

curvature of the AGS rod shall follow the contour of the neoprene insert.

1.13.11.3 The AGS preformed rod set shall be as detailed in clause 1.13.10.4 to

1.13.10.7 in general except for the following.

1.13.11.4 The length of the AGS preformed rods shall be such that it shall ensure

sufficient slipping strength as detailed under clause 1.13.4 and shall not

introduce unfavorable stress on the conductor under all operating



7

conditions. However the length of AGS preformed rods shall not be less

than that stipulated in the Standard Technical Particulars.

1.14 Envelope Type Suspension Clamp

1.14.1 The seat of the envelope type suspension clamp shall be smoothly rounded

& suitably curved at the ends. The lip edges shall have rounded bead. There

shall be at least two U-bolts for tightening of clamp body and keeper pieces

together. Hexagonal bolts and nuts with split-pins shall be used for

attachment of the clamp.

1.15 Dead end Assembly

1.15.1 The dead end assembly shall be suitable for specific Conductor.

1.15.2 The dead end assembly shall be compression type with provision for

comprising jumper terminal at one end. The angle of jumper terminal to be

mounted should be 30° with respect to the vertical line. The area of bearing

surface on all the connections shall be sufficient to ensure positive electrical

and mechanical contact and avoid local heating due to I2R losses. The

resistance of the clamp when compressed on Conductor shall not be more

than 75% of the resistance of equivalent length of Conductor.

1.15.3 Die compression areas shall be clearly marked on each dead-end assembly

designed for continuous die compressions and shall bear the words

‘COMPRESS FIRST’ suitably inscribed near the point on each assembly

where the compression begins. If the dead end assembly is designed for

intermittent die compressions it shall bear identification marks

‘COMPRESSION ZONE’ AND ‘NON-COMPRESSION ZONE’ distinctly

with arrow marks showing the direction of compressions and knurling

marks showing the end of the zones. The letters, number and other

markings on the finished clamp shall be distinct and legible. The

dimensional tolerances of the cross section of aluminium and steel dead end;

for dead end assembly for the specific conductor shall be as stipulated in the


1.15.4 The assembly shall not permit slipping of, damage to, or failure of the

complete conductor or any part there of at a load less than 95% of the

ultimate tensile strength of the conductor.

1.16 Balancing Weights

For holding the single suspension pilot insulator string used for jumper

connections from excessive deflection, suitable balancing weights, weighing

200 kg. are to be suspended through the line side yoke plate. It shall consist

of four weights, each weighing 50 Kgs. and shall be connected to the yoke

plate by means of eye bolt and shackle arrangement. The bottom weight



8

shall be provided with recess to shield the ends of eye bolts. The same shall

be suitable for use on specific transmission lines.

1.17 Fasteners: Bolts, Nuts and Washers

1.17.1 All bolts and nuts shall conform to IS:6639. All bolts and nuts shall be

galvanised as per IS-1367 - (Part 13)/IS-2629. All bolts and nuts shall have

hexagonal heads, the heads being forged out of solid truly concentric, and

square with the shank, which must be perfectly straight.

1.17.2 Bolts up to M16 and having length up to 10 times the diameter of the bolt

should be manufactured by cold forging and thread rolling process to obtain

good and reliable mechanical properties and effective dimensional control.

The shear strength of bolt for 5.6 grade should be 310 MPa minimum as per

IS-:12427. Bolts should be provided with washer face in accordance with

IS:1363 Part-1 to ensure proper bearing.

1.17.3 Nuts should be double chamfered as per the requirement of IS:1363 Part-III.

It should be ensured by the manufacturer that nuts should not be over

tapped beyond 0.4 mm oversize on effective diameter for size up to M16.

1.17.4 Fully threaded bolts shall not be used. The length of the bolt shall be such

that the threaded portion shall not extend into the place of contact of the

component parts.

1.17.5 All bolts shall be threaded to take the full depth of the nuts and threaded

enough to permit the firm gripping of the component parts but no further. It

shall be ensured that the threaded portion of the bolt protrudes not less than

3 mm and not more than 8 mm when fully tightened. All nuts shall fit and

tight to the point where shank of the bolt connects to the head.

1.17.6 Flat washers and spring washers shall be provided wherever necessary and

shall be of positive lock type. Spring washers shall be electro-galvanised.

The thickness of washers shall conform to IS:2016-1967.

1.17.7 The Contractor shall furnish bolt schedules giving thickness of components

connected. The nut and the washer and the length of shank and the threaded

portion of bolts and size of holes and any other special details of this nature.

1.17.8 To obviate bending stress in bolt, it shall not connect aggregate thickness

more than three time its diameter.

1.17.9 Bolts at the joints shall be so staggered that nuts may be tightened with

spanners without fouling.

1.17.10 To ensure effective in-process Quality control it is essential that the

manufacturer should have all the testing facilities for tests like weight of

zinc coating, shear strength, other testing facilities etc, in-house. The



9

manufacturer should also have proper Quality Assurance system, which

should be in line with the requirement of this specification and IS-.14000

services Quality System standard.

1.17.11 Fasteners of grade higher than 8.8 are not to be used and minimum grade

for bolt shall be 5.6.

1.18 Materials

The materials of the various components shall be as specified hereunder.

The Contractor shall indicate the material proposed to be used for each and

every component of hardware fittings stating clearly the class, grade or alloy

designation of the material, manufacturing process & heat treatment details

and the reference standards.

1.18.1 The details of materials for different component are listed as in Table-I

TABLE-1

(Details of Materials)

Sl.

No.

Name of

item

Material

treatment

Process of

Standard

Reference Remarks

1. Security

Clips

Stainless Steel/

Phospher

Bronze

- AISI 302 or

304-L/ IS-

1385

2. Arcing

Horn

Mild Steel Rod/

Tube Type

Hot dip

galvanised

As per IS-

226

or IS-2062

3. Ball

Fittings,

Socket, all

shackles

links cleves

Class-IV Steel Drop forged

& normalized

Hot dip

galvanised

As per IS:

2004

4. Yoke Plate Mild Steel Hot dip

galvanized

As per IS-

226

or IS-2062

5. Sag

Adjustment

plate

Mild Steel Hot dip

galvanized

As per IS-

226

or IS-2062

6(a). Corona

Control

ring/

Grading

ring

High Strength

Al. Alloy tube

(6061/ 6063/1100

type or 65032/

63400 Type)

Heat treated

Hot dip

galvanized

ASTM-B429

or as per IS

Mechanical

strength of

welded joint

shall not be

less than 20

KN



10

6(b). Supporting

Brackets &

Mounting

Bolts

High Strentgth

Al Alloy 7061/

6063/

65032/63400

Type) or Mild

Steel

Heat treated

Hot dip

galvanized

ASTM-B429

or as per

IS:226 or

IS:2062

7(a). Envelope

type

Clamp:

Clamp

Body,

Keeper

Piece

High Strength

Al. Alloy 4600/

LM-6 or

6061/65032 or

6063/63400

Casted or

forged &

Heat treated

IS:617 or

ASTM-B429

7(b). Envelope

type

Clamp:

Cotter

bolts/

Hangers,

Shackles,

Brackets

Mild Steel Hot dip

galvanised

As per IS-

226

or IS-2062

7(c). Envelope

type

Clamp:

U Bolts

Stainless Steel

or High

Strength

Al alloy 6061/

6063 or

65032/63400

Forged & &

Heat treated

AISI 302 or

304-L

ASTM-B429

8(a). Dead End

Assembly:

Outer

Sleeve

EC grade Al of

purity not less

than 99.50%

8(b). Steel Sleeve Mild Steel Hot Dip

Galvanised

IS:226/

IS-2062

Note : Alternate materials conforming to other national standards of other countries

also may be offered provided the properties and compositions of these are close to the

properties and compositions of material specified. Bidder should furnish the details of

comparison of material offered viz a viz specified in the bid or else the bids are liable

to be rejected.

1.19 Workmanship

1.19.1 All the equipment shall be of the latest design and conform to the best

modern practices adopted in the Extra High Voltage field. The Contractor

shall offer only such equipment as guaranteed by him to be satisfactory and

suitable for the rated transmission lines and will give continued good

performance.



11

1.19.2 The design, manufacturing process and quality control of all the materials

shall be such as to give the specified mechanical rating, highest mobility,

elimination of sharp edges and corners to limit corona and radio-

interference, best resistance to corrosion and a good finish.

1.19.3 All ferrous parts including fasteners shall be hot dip galvanised, after all

machining has been completed. Nuts may, however, be tapped (threaded)

after galvanising and the threads oiled. Spring washers shall be electro

galvanised. The bolt threads shall be undercut to take care of the increase in

diameter due to galvanising. Galvanising shall he done in accordance with

IS:2629-1985/IS-1367(Part 13) and shall satisfy the tests mentioned in IS:2633-

1986.

1.19.4 Before ball fittings are galvanised. all die flashing on the shank and on the

bearing surface of the ball shall be carefully removed without reducing the

dimensions below the design requirements.

1.19.5 The zinc coating shall be perfectly adherent, of uniform thickness, smooth,

reasonably bright, continuous and free from imperfections such as flux, ash

rust, stains, bulky white deposits and blisters. The zinc used for galvanising

shall be Zinc of any grade in IS: 209:1992 ingot(fourth revision) or

IS:13229:1991.

1.19.6 Pin balls shall be checked with the applicable ‚GO‛ gauges in at least two

directions. one of which shall be across the line of die flashing, and the other

90o to this line. "NO GO" gauges shall not pass in any direction.

1.19.7 Socket ends, before galvanising, shall be of uniform contour. The bearing

surface of socket ends shall be uniform about the entire circumference

without depressions of high spots. The internal contours of socket ends

shall be concentric with the axis of the fittings as per IS:2486/IEC : 120.

The axis of the bearing surfaces of socket ends shall be coaxial with the axis

of the fittings. There shall be no noticeable tilting of the bearing surfaces

with the axis of the fittings.

1.19.8 In case of casting, the same shall be free from all internal defects like

shrinkage, inclusion, blow holes, cracks etc. Pressure die casting shall not be

used for casting of components with thickness more than 5 mm.

1.19.9 All current carrying parts shall be so designed and manufactured that

contact resistance is reduced to minimum.

1.19.10 No equipment shall have sharp ends or edges, abrasions or projections and

cause any damage to the conductor in any way during erection or during

continuous operation which would produce high electrical and mechanical



12

stresses in normal working. The design of adjacent metal parts and mating

surfaces shall be such as to prevent corrosion of the contact surface and to

maintain good electrical contact under service conditions.

1.19.11 All the holes shall be cylindrical, clean cut and perpendicular to the plane of

the material. The periphery of the holes shall be free from burrs.

1.19.12 All fasteners shall have suitable corona free locking arrangement to guard

against vibration loosening.

1.19.13 Welding of aluminium shall be by inert gas shielded tungsten arc or inert

gas shielded metal arc process. Welds shall be clean, sound, smooth,

uniform without overlaps, properly fused and completely sealed. There

shall be no cracks, voids incomplete penetration, incomplete fusion, under-

cutting or inclusions. Porosity shall be minimised so that mechanical

properties of the aluminium alloys are not affected. All welds shall be

properly finished as per good engineering practices.

1.20 Bid Drawings

1.20.1 The Contractor shall furnish full description and illustrations of materials

offered.

1.20.2 Fully dimensioned drawings of the complete insulator string hard wares

and their component parts showing clearly the following arrangements shall

be furnished along with the bid. Weight, material and fabrication details of

all the components should be included in the drawings.

(i) Attachment of the hanger or strain plate.

(ii) Suspension or dead end assembly.

(iii) Arcing horn attachment to the string as specified in clause 1.8 of this

technical Specification.

(iv) Yoke plates

(v) Hardware fittings of ball and socket type for inter connecting units to

the top and bottom Yoke plates.

(vi) Corona control rings/grading ring attachment to conductor and other

small accessories.

(vii) Links with suitable fittings.

(viii) Details of balancing weights and arrangements for their attachment

in the single suspension pilot insulator string.



13

1.20.3 All drawings shall be identified by a drawing number and contract number.

All drawings shall be neatly arranged. All drafting & lettering shall be

legible. The minimum size of lettering shall be 3 mm. All dimensions &

dimensional tolerances shall be mentioned in mm.

The drawings shall include :

(i) Dimensions and dimensional tolerance.

(ii) Material, fabrication details including any weld details & any

specified finishes & coatings. Regarding material designation &

reference of standards are to be indicated.

(iii) Catalogue No.

(iv) Marking

(v) Weight of assembly

(vi) Installation instructions

(vii) Design installation torque for the bolt or cap screw.

(viii) Withstand torque that may be applied to the bolt or cap screw

without failure of component parts.

(ix) The compression die number with recommended compression

pressure.

(x) All other relevant terminal details.

1.20.4 After placement of award, the Contractor shall submit fully dimensioned

drawing including all the components in four (4) copies to the Employer for

approval. After getting approval from the Employer and successful

completion of all the type tests, the Contractor shall submit thirty (30) more

copies of the same drawings to the Employer for further distribution and

field use at Employer 's end.

2.0 Accessories for Conductor

2.1 General

2.1.1 This portion (under clause 2.0) details the technical particulars of the

accessories for Conductor.

2.1.2 2.5% extra fasteners and retaining rods shall be provided.

2.2 Mid Span Compression Joint

2.2.1 Mid Span Compression Joint shall be used for joining two lengths of

conductor. The joint shall have a resistively less than 75% of the resistivity



14

of equivalent length of conductor. The joint shall not permit slipping off,

damage to or failure of the complete conductor or any part there of at a load

less than 95% of the ultimate tensile strength of the conductor.

2.2.2 The joint shall be made of steel and aluminium sleeves for jointing the steel

core and aluminium wires respectively. The steel sleeve should not crack or

fail during compression. The steel sleeve shall be hot dip galvanised. The

aluminium sleeve shall have aluminium of purity not less than 99.5%. The

dimensions and dimensional tolerances of mid span compression joint shall

be as per Standard Technical Particulars.

2.3 T-Connector

T-Connector of compression type shall be used for jumper connection at

transposition tower. It shall be manufactured out of 99.5% pure aluminium

and shall be strong enough to withstand normal working loads. The T-

connector shall have a resistivity across jumper less than 75% resistivity of

equivalent length of conductor. The T-connector shall not permit slipping

off, damage to or failure of complete conductor. The welded portions shall

be designed for 30 kN axial tensile load. Leg sleeve of T-connector should be

kept at an angle of 15 deg. from vertical and horizontal plane of the

conductor in order to minimise jumper pull at the welded portion. The

dimensions and dimensional tolerances of T-connector shall be as per


2.4 Repair Sleeve

Repair Sleeve of compression type shall be used to repair conductor with not

more than two strands broken in the outer layer. The sleeve shall be

manufactured from 99.5% pure aluminium and shall have a smooth surface.

The repair sleeve shall comprise of two pieces with a provision of seat for

sliding of the keeper piece. The edges of the seat as well as the keeper piece

shall be so rounded that the conductor strands are not damaged during

installation. The dimensions and dimensional tolerances of repair sleeve

shall be as per Standard Technical Particulars.

2.5 Vibration Damper (To be used in Single or Twin Bundle Conductor)

2.5.1 Vibration dampers of 4R-stockbridge type with four (4) different resonances

spread within the specified Aeolian frequency band width corresponding to

wind speed of 1 m/s to 7 m/s shall be used at suspension and tension points

on each conductor in each span along with bundle spacers to damp out

Aeolian vibration as mentioned hereinafter.

2.5.2 Alternate damping systems or ‚Dogbone‛ dampers offering equivalent or

better performance also shall be accepted provided the manufacturer meets



15

the qualifying requirements stipulated in the Specifications. Relevant

technical documents to establish the technical suitability of alternate systems

shall be furnished by the Bidder along with the bid.

2.5.3 One damper minimum on each side per Conductor/Sub-conductor for

suspension points and two dampers minimum on each side per

conductor/sub-conductor for tension points shall be used for ruling design

span.

2.5.4 The Bidder may offer damping system involving more number of dampers

per ruling design span than the specified. However suitable price

compensation shall be considered for evaluation. For the purpose of price

compensation 80% of the towers as suspension locations and 20% of the

towers as tension locations and all the spans shall be assumed to be ruling

design spans.

2.5.5 The clamp of the vibration damper shall be made of high strength

aluminium alloy of type LM-6. It shall be capable of supporting the damper

and prevent damage or chafing of the conductor during erection or

continued operation. The clamp shall have smooth and permanent grip to

keep the damper in position on the conductor without damaging the strands

or causing premature fatigue failure of the conductor under the clamp. The

clamp groove shall be in uniform contact with the conductor over the entire

clamping surface except for the rounded edges. The groove of the clamp

body and clamp cap shall be smooth, free from projections, grit or other

materials which could cause damage to the conductor when the clamp is

installed. Clamping bolts shall be provided with self locking nuts and

designed to prevent corrosion of threads or loosening in service.

2.5.6 The messenger cable shall be made of high strength galvanised steel/stain

less steel with a minimum strength of 135 kg/sqmm. It shall be of preformed

and post formed quality in order to prevent subsequent droop of weight and

to maintain consistent flexural stiffness of the cable in service. The number of

strands in the messenger cable shall be 19. The messenger cable other than

stainless steel shall be hot dip galvanised in accordance with the

recommendations of IS:4826 for heavily coated wires.

2.5.7 The damper mass shall be made of hot dip galvanised mild steel/cast iron or

a permanent mould cast zinc alloy. All castings shall be free from defects

such as cracks, shrinkage, inclusions and blowholes etc. The surface of the

damper masses shall be smooth.

2.5.8 The damper clamp shall be casted over the messenger cable and offer

sufficient and permanent grip on it. The messenger cable shall not slip out

of the grip at a load less than the mass pull-off value of the damper. The



16

damper masses made of material other-than zinc alloy shall be fixed to the

messenger cable in a suitable manner in order to avoid excessive stress

concentration on the messenger cables which shall cause premature fatigue

failure of the same. The messenger cable ends shall be suitably and

effectively sealed to prevent corrosion. The damper mass made of zinc alloy

shall be casted over the messenger cable and have sufficient and permanent

grip on the messenger cable under all service conditions.

2.5.9 The damper assembly shall be so designed that it shall not introduce radio

interference beyond acceptable limits.

2.5.10 The vibration damper shall be capable of being installed and removed from

energised line by means of hot line technique. In addition, the clamp shall be

capable of being removed and reinstalled on the conductor at the designated

torque without shearing or damaging of fasteners.

2.5.11 The contractor must indicate the clamp bolt tightening torque to ensure

that the slip strength of the clamp is maintained between 2.5 kN and 5 kN.

The clamp when installed on the conductor shall not cause excessive

stress concentration on the conductor leading to permanent deformation

of the conductor strands and premature fatigue failure in operation.

2.5.12 The magnetic power loss of vibration damper shall not exceed the limit as

stipulated in the Standard Technical Particulars.

2.5.13 The vibration analysis of the system, with and without damper and dynamic

characteristics of the damper as detailed under Annexure-A, shall have to be

submitted. The technical particulars for vibration analysis and damping

design of the system are as follows:

Sl. No. Description Technical particulars

1. Span length in meters

i) Ruling design span As per Section-I

ii) Maximum span 1100 meters

iii) Minimum span 100 meters

2. Configuration As per Section-I of this

Specification

3. Tensile load in Conductor at

temperature of 0 deg. C and still air

As per sag tension

calculations.

4. Armour rods used Standard preformed

armour rods/AGS

5. Maximum permissible dynamic

strain

+/- 150 micro strains



17

2.5.14 The damper placement chart for spans ranging from 100m to 1100m shall be

submitted by the Bidder. Placement charts should be duly supported with

relevant technical documents and sample calculations.

2.5.15 The damper placement charts shall include the following

(1) Location of the dampers for various combinations of spans and line

tensions clearly indicating the number of dampers to be installed per

conductor per span.

(2) Placement distances clearly identifying the extremities between which the

distances are to be measured.

(3) Placement recommendation depending upon type of suspension clamps

(viz Free center type/Armour grip type etc.)

(4) The influence of mid span compression joints, repair sleeves and armour

rods (standard and AGS) in the placement of dampers.

2.6 Bundle Spacer (for Twin Bundle Conductor) & Rigid Spacer (for Quad /

Twin Bundle Conductor)

2.6.1 Armour grip bundle spacers shall be used to maintain the spacing of 450 mm

between the two sub-conductors of each bundle under all normal working

conditions.

2.6.2 Spacers offering equivalent or better performance shall also be accepted

provided offer meets the qualifying requirements stipulated in the

Specification.

2.6.3 The offer shall include placement charts recommending the number of

spacers per phase per span and the sub span lengths to be maintained

between the spacers while installing on the twin bundle conductors.

2.6.3.1 The placement of spacers shall be in such a way that adjacent sub spans are

sufficiently detuned and the critical wind velocity of each sub span shall be

kept more than 30 km/hr and to avoid clashing of sub conductors. The

placement shall ensure bundle stability under all operating conditions.

2.6.3.2 The placement chart shall be provided for spans ranging from 100 m to

1100m. The number of spacers recommended for a ruling design span of

400m shall however be seven with no sub-span greater than 70m and no end

sub-span longer than 40m.

2.6.3.3 The Bidder may offer more number of spacers per ruling design span than

the specified. However, in such case, suitable price compensation shall be



18

considered for evaluation. For the purpose of price compensation, all the

spans shall be assumed to be ruling design spans.

2.6.3.4 The Bidder shall also furnish all the relevant technical documents in support

of their placement charts along with the bid.

2.6.4 Jumpers at tension points shall also be fitted with spacers so as to limit the

length of free conductor to 3.65 m and to maintain the sub conductor spacing

of 450 / 457 mm. Bidder shall quote for rigid spacer for jumper. It shall meet

all the requirements of spacer used in line except for its vibration

performance. Spacers requiring retaining rods shall not be quoted for

jumpers.

2.6.5 The spacer offered by the Bidder shall satisfy the following requirements.

2.6.5.1 Spacer shall restore normal spacing of the sub conductors after displacement

by wind, electromagnetic and the electrostatic forces under all operating

conditions including the specified short circuit level without permanent

deformation damage either to conductor or to the assembly itself. They shall

have uniform grip on the conductor

2.6.5.2 For spacer requiring retaining rods, the retaining rods shall be designed for

the specified conductor size. The preformed rods shall be made of high

strength, special aluminium alloy of type 6061/65032 and shall have

minimum tensile strength of 35 kg/sq.mm. The ends of retaining rods should

be ball ended. The rods shall be heat-treated to achieve specified mechanical

properties and give proper resilience and retain the same during service.

2.6.5.3 Four number of rods shall be applied on each clamps to hold the clamp in

position. The minimum diameter of the rods shall be 7.87 + 0.1 mm and the

length of the rods shall not be less than 1100 mm.

2.6.5.4 Where elastomer surfaced clamp grooves are used, the elastomer shall be

firmly fixed to the clamp. The insert should be forged from aluminium alloy

of type 6061/65032. The insert shall be duly heat treated and aged to retain

its consistent characteristics during service.

2.6.5.5 Any nut used shall be locked in an approved manner to prevent vibration

loosening. The ends of bolts and nuts shall be properly rounded for specified

corona performance or suitably shielded.

2.6.5.6 Clamp with cap shall be designed to prevent its cap from slipping out of

position when being tightened.

2.6.5.7 The clamp grooves shall be in uniform contact with the conductor over the

entire surface, except for rounded edges. The groove of the clamp body and



19

clamp cap shall be smooth and free of projections, grit or other material

which cause damage to the conductor when the clamp is installed.

2.6.5.8 For the spacer involving bolted clamps, the manufacturer must indicate the

clamp bolt tightening torque to ensure that the slip strength of the clamp is

maintained between 2.5 kN and 5 kN. The clamp when installed on the

conductor shall not cause excessive stress concentration on the conductor

leading to permanent deformation of the conductor strands and premature

fatigue failure in operation.

2.6.5.9 Universal type bolted clamps, covering a range of conductor sizes, will not

be permitted.

2.6.5.10 No rubbing, other than that of the conductor clamp hinges or clamp swing

bolts, shall take place between any parts of the spacer. Joint incorporating a

flexible medium shall be such that there is no relative slip between them.

2.6.5.11 The spacer shall be suitably designed to avoid distortion or damage to the

conductor or to themselves during service.

2.6.5.12 Rigid spacers shall be acceptable only for jumpers.

2.6.5.13 The spacer shall not damage or chafe the conductor in any way which might

affect its mechanical and fatigue strength or corona performance.

2.6.5.14 The clamping system shall be designed to compensate for any reduction in

diameter of conductor due to creep.

2.6.5.15 The spacer assembly shall not have any projections, cuts, abrasions etc. or

chattering parts which might cause corona or RIV.

2.6.5.16 The spacer tube shall be made of aluminium alloy of type 6061/65032 or

6063/63400. If fasteners of ferrous material are used, they shall conform to

and be galvanised conforming to relevant Indian Standards. The spacer

involving ferrous fasteners shall not have magnetic power loss more than

that stipulated in the Standard Technical Particulars.

2.6.5.17 Elastomer, if used, shall be resistant to the effects of temperature up to 95

deg.C, ultraviolet radiation and other atmospheric contaminants likely to be

encountered in service. It shall have good fatigue characteristics. The

physical properties of the elastomer shall be of approved standard.

2.6.5.18 The spacer assembly shall have electrical continuity. The electrical resistance

between the sub-conductor across the assembly in case of spacer having

elastomer clamp grooves shall be suitably selected by the manufacturers to

ensure satisfactory electrical performance and to avoid deterioration of

elastomer under all service conditions.



20

2.6.5.19 The spacer assembly shall have complete ease of installation and shall be

capable of removal/reinstallation without any damage.

2.6.5.20 The spacer assembly shall be capable of being installed and removed from

the energised line by means of hot line technique.

2.7 Material and Workmanship

2.7.1 All the equipment shall be of the latest proven design and conform to the

best modern practice adopted in the extra high voltage field. The Bidder

shall offer only such equipment as guaranteed by him to be satisfactory and

suitable for transmission line application of the rated voltage with single/

bundle conductors and will give continued good performance.

2.7.2 The design, manufacturing process and quality control of all the materials

shall be such as to achieve requisite factor of safety for maximum working

load, highest mobility, elimination of sharp edges and corners, best

resistance to corrosion and a good finish.

2.7.3 All ferrous parts shall be hot dip galvanised, after all machining has been

completed. Nuts may, however, be tapped (threaded) after galvanising and

the threads oiled. Spring washers shall be electro galvanised as per grade 4

of IS-1573-1970. The bolt threads shall be undercut to take care of increase in

diameter due to galvanising. Galvanising shall be done in accordance with

IS:2629/IS-1367 (Part-13) and satisfy the tests mentioned in IS-2633. Fasteners

shall withstand four dips while spring washers shall withstand three dips.

Other galvanised materials shall have a minimum overall coating of Zinc

equivalent to 600 gm/sq.m and shall be guaranteed to withstand at least six

dips each lasting one minute under the standard Preece test for galvanising

unless otherwise specified.

2.7.4 The zinc coating shall be perfectly adherent, of uniform thickness, smooth,

reasonably bright, continuous and free from imperfections such as flux, ash,

rust stains, bulky white deposits and blisters. The zinc used for galvanising

shall be of grade Zn.99.95 as per IS:209.

2.7.5 In case of castings, the same shall be free from all internal defects like

shrinkage, inclusion, blow holes. cracks etc.

2.7.6 All current carrying parts shall be so designed and manufactured that

contact resistance is reduced to minimum and localised heating

phenomenon is averted.

2.7.7 No equipment shall have sharp ends or edges, abrasions or projections and

shall not cause any damage to the conductor in any way during erection or

during continuous operation which would produce high electrical and

mechanical stresses in normal working. The design of adjacent metal parts



21

and mating surfaces shall be such as to prevent corrosion of the contact

surface and to maintain good electrical contact under all service conditions.

2.7.8 Particular care shall be taken during manufacture and subsequent handling

to ensure smooth surface free from abrasion or cuts.

2.7.9 The fasteners shall conform to the requirements of IS:6639. All fasteners and

clamps shall have corona free locking arrangement to guard against

vibration loosening.

2.8 Compression Markings

Die compression areas shall be clearly marked on each equipment designed

for continuous die compressions and shall bear the words ‘COMPRESS

FIRST’ ‘suitably inscribed on each equipment where the compression begins.

If the equipment is designed for intermittent die compressions, it shall bear

the identification marks ‘COMPRESSION ZONE’ and ‘NON-

COMPRESSION ZONE’ distinctly with arrow marks showing the direction

of compression and knurling marks showing the end of the zones. The

letters, number and other markings on finished equipment shall be distinct

and legible.

2.9 Bid Drawings

2.9.1 The Bidder shall furnish detailed dimensioned drawings of the equipments

and all component parts. Each drawing shall be identified by a drawing

number and Contract number. All drawings shall be neatly arranged. All

drafting and lettering shall be legible. The minimum size of lettering shall be

3 mm. All dimensions and dimensional tolerances shall be mentioned in

mm.

2.9.2 The drawings shall include

(i) Dimensions and dimensional tolerances

(ii) Material. fabrication details including any weld details and any specified

finishes and coatings. Regarding material, designations and reference of

standards are to be indicated.

(iii) Catalogue No.

(iv) Marking

(v) Weight of assembly

(vi) Installation instructions

(vii) Design installation torque for the bolt or cap screw



22

viii) Withstand torque that may be applied to the bolt or cap screw without

failure of component parts

(ix) The compression die number with recommended compression pressure.

(x) All other relevant technical details

2.9.3 Placement charts for spacer and damper

2.9.4 The above drawings shall be submitted with all the details as stated above

along with the bid document. After the placement of award. the Contractor

shall again submit the drawings in four copies to the Purchaser for approval.

After Purchaser’s approval and successful completion of all type tests, 10

(ten) more sets of drawings shall be submitted to Purchaser for further

distribution and field use at Purchaser’s end.

3.0 G.S. Earth wire Accessories

3.1 General

3.1.1 This portion Specify the details of the technical particulars of the accessories

for Galvanised Steel Earth wire.

3.1.2 2.5% extra fasteners shall be supplied.

3.2 Mid Span Compression Joint

Mid Span Compression Joint shall be used for joining two lengths of earth

wire. The joint shall be made of mild steel with aluminium encasing. The

steel sleeve should not crack or fail during compression. The Brinnel

Hardness of steel should not exceed the value as stipulated in the Standard

Technical Particulars. The steel sleeve shall be hot dip galvanised. The

aluminium sleeve shall have aluminium of purity not less than that

stipulated in the Standard Technical Particulars. Filler aluminium sleeve

shall also be provided at the both ends. The joints shall not permit slipping

off, damage to or failure of the complete earth wire or any part thereof at a

load not less than 95% of the ultimate tensile strength of the earth wire. The

joint shall have resistivity less than 75% of resistivity of equivalent length of

earth wire. The dimensions and the dimensional tolerances of the joint shall

be as stipulated in the Standard Technical Particulars.

3.3 Vibration Damper

3.3.1 Vibration dampers of 4R-Stockbridge type with four (4) different frequencies

spread within the specified aeolian frequency band-width corresponding to

wind speed of 1m/s to 7 m/s shall be used for suspension and tension points



23

on each earth wire in each span to damp out aeolian vibrations as mentioned

herein after.

3.3.2 Alternate damping systems or ‚Dogbone‛ dampers offering equivalent or

better performance also shall be acceptable provided the manufacturer

meets the qualifying requirements stipulated in the Specifications. Relevant

technical documents to establish the technical suitability of alternate systems

shall be furnished by the Bidder along with the bid.

3.3.3 One damper minimum on each side per earth wire at suspension points and

two dampers on each side per earth wire at tension points shall be used for

ruling design span of 400 meters for 400 kV line and design span of 350

meters for 220 kV line.

3.3.4 The Bidder may offer damping system involving more number of dampers

per ruling design span than the specified. However suitable price

compensation shall be considered for evaluation. For the purpose of price

compensation 80% of towers as suspension locations and 20% of the towers

as tension locations and all the spans assumed to be ruling design spans.

3.3.5 The clamp of the vibration damper shall be made of aluminium alloy. It

shall be capable of supporting the damper during installation and prevent

damage or chaffing of the earth wire during erection or continued operation.

The clamp shall have smooth and permanent grip to keep the damper in

position on the earth wire without damaging the strands or causing

premature fatigue failure of the earth wire under the clamp. The clamp

groove shall be in uniform contact with the earth wire over the entire

clamping surface except for the rounded edges. The groove of the clamp

body and clamp cap shall be smooth, free from projections, grit or materials

which could cause damage to the earth wire when the clamp is installed.

Clamping bolts shall be provided with self locking nuts designed to prevent

corrosion of the threads or loosening during service.

3.3.6 The messenger cable shall be made of high strength galvanised

steel/stainless steel with a minimum strength of 135 Kg/sq.mm. It shall be of

preformed and post formed quality in order to prevent subsequent droop of

weights and to maintain consistent flexural stiffness of the cable in service.

The number of standards in the messenger cable shall be 19. The messenger

cable ends shall be suitably and effectively sealed to prevent corrosion.

3.3.7 The damper mass shall be made of hot dip galvanised mild steel/cast iron or

a permanent mould cast zinc alloy. All castings shall be free from defects

such as cracks, shrinkages, inclusions and blow holes etc. The inside and

outside surfaces of the damper masses shall be smooth.



24

3.3.8 The vibration analysis of the system, with and without damper, dynamic

characteristic of the damper as detailed under Annexure-A, shall have to be

submitted by the Bidder along with his bid. The technical particulars for

vibration analysis and damping design of the system are as follows:

Sl. No. Description Technical particulars

For 7/3.35 mm GS Earthwire

1. Span length in meters

i) Ruling design span 350 meters

ii) Maximum span 1100 meters

iii) Minimum span 100 meters

2. Tensile load in Conductor at temperature of

0 deg. C and still air

As per sag tension

calculations.

3. Armour rods used Standard preformed

armour rods/AGS

4. Maximum permissible dynamic strain +/- 150 micro strains

3.3.9 The damper placement chart for spans ranging from 100 m to 1100 m shall

be submitted by the Bidder. All the placement charts should be duly

supported by relevant technical documents.

3.3.10 The damper placement charts shall include the following:

(1) Location of the dampers for various combinations of spans and line

tensions clearly indicating number of dampers to be installed per

earth wire per span.

(2) Placement distances clearly identifying the extremities between

which the distances are to be measured.

(3) Placement recommendation depending upon type of suspension

clamps (viz, free center type/trunion type etc.)

(4) The influence of mid span compression joints in the placement of

dampers.

3.4 Flexible Copper Bond

The flexible copper bond shall be circular in cross-section of minimum 34

sq.mm equivalent copper area and not less than 500 mm in length. It shall

consist of 259 wires of 0.417 mm dia. tinned copper conductor. It shall be

laid up as 7 stranded ropes, each of 37 bunched wires. The tinning shall be

as per relevant Indian Standard. Two tinned copper connecting lugs shall be

press jointed to either ends of the flexible copper cable. One lug shall be

suitable for 12 mm, dia. bolt and the other for 16 mm dia bolt. The complete



25

assembly shall also include one 16 mm dia., 40 mm long HRH MS Bolt hot

dip galvanised with nut and lock washer.

3.5 Suspension Clamp

3.5.1 Standard anchor shackle/twisted shackle for earth wire suspension clamp

shall be supplied for attaching to the hanger plate of tower.

3.5.2 At all suspension towers, suitable suspension clamps shall be used to

support the required earth wire. The clamps shall be of either free center

type or trunion type and shall provide adequate area of support to the earth

wire. The groove of the clamp shall be smooth, finished in an uniform

circular or oval shape and shall slope downwards in a smooth curve to

avoid edge support and hence to reduce the intensity of bending moment on

earth wire.

3.5.3 There shall be no sharp point in the clamps coming in contact with earth

wire. There shall not be any displacement in the configuration of the earth

wire strands nor shall the strands be unduly stressed in final assembly

during working conditions.

3.5.4 The clamping piece and the clamp body shall be clamped by at least two U-

bolts of size not less than 10 mm diameter having one nut and one 3 mm

thick lock nut with washer on each of its limbs. Suspension clamps shall be

provided with inverted type U-bolts. One limb of the U-bolt shall be long

enough to accommodate the lug of the flexible copper bond.

3.5.5 The Contractor shall supply all the components of the suspension assembly

including shackles, bolts, nuts, washers, split pin etc. The total drop of the

suspension assembly from the center point of the attachment to the center

point of the earth wire shall not exceed 150 mm. The design of the assembly

shall be such that the direction of run of the earth wire shall be same as that

of the conductor.

3.5.6 The complete assembly shall be guaranteed for slip and breaking strength of

values indicated in the Standard Technical Particulars.

3.6 Tension Clamp

3.6.1 At all tension towers suitable compression type tension clamps shall be used

to hold the required galvanised steel earth wire. Anchor shackle shall be

supplied which shall be suitable for attaching the tension clamp to strain

plates.

3.6.2 The clamps shall have adequate area of bearing surface to ensure positive

electrical and mechanical contact and shall not permit any slip to the earth



26

wire under working tension and vibration conditions. The angle of jumper

terminal to be mounted should be 30 deg. with respect to the vertical line.

3.6.3 The clamps shall be made of mild steel with aluminium encasing. The steel

should not crack or fail during compression. The Brinnel hardness of steel

sleeve shall not exceed 200. The steel sleeve shall be hot dip galvanised. The

aluminium encasing shall have aluminium of purity not less than 99.5%.

Filler aluminium sleeve shall also be provided at the end.

3.6.4 The complete assembly shall be so designed as to avoid undue bending in

any part of the clamp and shall not produce any hindrance to the

movements of the clamps in horizontal or vertical directions.

3.6.5 The slip strength of the assembly shall not be less than 95% of the ultimate

strength of the earth wire.

3.6.6 The clamps shall be complete with all the components including anchor

shackle, bolts, nuts, washers, split pin, jumper arrangement etc.

3.7 Material and Workmanship

Same as Clause 2.8 of this section

3.8 Compression Marking


3.9 Bid Drawings


4.0 Standard technical particulars

4.1 The Standard technical particulars to adhered by the contractor /

manufacturer are furnished below:

A. Standardized Technical Particulars of Hardware Fittings and Accessories

of TWIN ACSR BISON conductor for 220 kV Transmission Line

Suspension hardware fittings for twin ACSR BISON Conductor

Sl. Description Unit Particulars/ Value

Single “I”

Suspension

Fittings with

Single

suspension

Pilot Fitting

with

AGS

clamp

Free

Centre

clamp

Envelope

clamp

1. Maximum magnetic power loss of Watt 4 4 8



27

one suspension assembly at sub-

conductor current of 600 amperes

2. Slipping strength of suspension

assembly

KN 15-22 15-22 15-22

3. Particulars of standard/ AGS

preformed armour rod set for

suspension assembly

a) No. of rods per set No. 12 12 NA

b) Direction of lay Right

hand

Right

hand

NA

c) Overall length after fitting on

conductor

mm 2080 2540 NA

d) Diameter of each rod mm 7.87 7.87 NA

e) Tolerance in

i) Diameter of each rod ±mm 0.10 0.10 NA

ii) Length of each rod ±mm 25 25 NA

iii) Difference of length between

the longest and shortest rod

in a set

±mm 13 13 NA

f) Type of Aluminium alloy used for

manufacture of PA rod set

6061/

65032

6061/

65032

NA

g) Minimum UTS of each rod Kg/mm2 35 35 NA

4. Particulars of Elastomer (For AGS Clamp only)

a) Type of elastomer Chlor

opren

e/Neo

prene

Rubbe

r

NA NA

b) Shore hardness of elastomer 65 to

85

NA NA

c) Temperature range for which

elastomer is designed

Upto

95o C

NA NA

d) Moulded on insert Yes NA NA

5. Mechanical strength of suspension

fitting(excluding suspension clamp)

KN 70 70

6. Mechanical strength of suspension

clamp

KN 70 70

7. Purity of Zinc used for galvanising % 99.95 99.95

8. Min. No. of dips in standard preece

test the ferrous parts can withstand

No. a) Fasteners: 4 dips of 1 minute

b) Spring washers: 3 dips of 1 minute

c) all others: 6 dips of 1 minute



28

Tension hardware fittings for Twin ACSR BISON Conductor


Double

Tension

1. Mechanical strength of Tension

fitting(excluding dead end clamp)

KN 2x120

2. Type of dead end assembly Compression

3. Compression pressure MT 100

4. Maximum electrical resistance of

dead end assembly as a

percentage of equivalent length of

Conductor

% 75

5. Slip strength of dead end

assembly

KN 95% of UTS of ACSR BISON

6. Purity of Zinc used for

galvanising

% 99.95

7. Min. No. of dips in standard

preece test the ferrous parts can

withstand.

Nos

.

a) Fasteners: 4 dips of 1 minute

b) Spring washers: 3 dips of 1 minute

c) all others: 6 dips of 1 minute

Mid span compression Joint for ACSR BISON Conductor


Aluminium

Sleeve

Steel Sleeve

1. Material of Joint Aluminium of

purity 99.5%

Mild Steel(Fe-

410, IS:2062)

2. Range of Hardness of the steel sleeve

(Brinnel hardness)

BHN From 100 to 200

3. Weight of Zinc coating for steel sleeve gm/m2 610

4. Dimension of sleeve Before compression Aluminum

sleeve

Steel sleeve

i) Inside diameter mm To be decided during detailed

engineering ii) Outside diameter mm

iii) Length mm 710 ± 5 241 ± 5

5. Dimensions of Sleeve after compression Aluminum

sleeve

Steel sleeve

i) Outside dimension(Corner to corner) mm To be decided during detailed

engineering ii) Outside dimension ( face to face) mm

6. Slip strength KN 95% of UTS of ACSR BISON

7. Maximum resistance of the compressed unit

expressed, as percentage of the resistance of

% 75



29

equivalent length of bare conductor.

8. Minimum corona Extinction voltage kV

(rms) under dry condition

kV 154

9. Maximum Radio Interference Voltage at 1

MHz for phase to earth voltage of 154 kV


Micro

Volts

1000

Repair sleeve for ACSR BISON Conductor


1. Material Aluminium of minimum purity

99.5%

2. Dimension of Aluminum sleeve Before compression

i) Inside diameter mm To be decided during detailed

engineering ii) Outside diameter mm

iii) Length mm 275.00 ± 5.0

3. Dimensions of Aluminum Sleeve after compression

i) Outside dimension(Corner to corner) mm To be decided during detailed

engineering ii) Outside dimension (face to face) mm



kV 154

5. Maximum Radio Interference Voltage at 1

MHz for phase to earth voltage of 154 kV


Micro

Volts

1000

Vibration Damper for ACSR BISON conductor (for twin bundle conductor only)


1. Type of Damper 4R-Stockbridge type

2. Materials of components

a) Damper masses Cast iron/mild steel/Zinc alloy

duly hot dip galvanised

b) Clamp Aluminum alloy 4600

c) Messenger cable High tensile strength

galvanized steel

3. Number of strands in stranded messenger

cable

Nos. 19

4. Minimum ultimate tensile strength of

stranded messenger cable

Kg/mm2 135

5. Slip strength of stranded messenger cable

(mass pull off)

KN 5

6. Slipping strength of damper clamp

(a) Before fatigue test KN 2.5

(b) After fatigue test KN 2



30

7. Resonance frequencies range Hz 5 to 40

8. Maximum magnetic power loss per

vibration damper watts for 600 amps, 50 Hz

Alternating Current

Watts 1



kV 154

10. Maximum Radio Interference Voltage (RIV)

at 1 MHz for phase to earth voltage of154 kV


Micro

Volts

1000

11. Percentage variation in reactance after

fatigue test in comparison with that . before

fatigue test

% +/-40 (Maximum)

12. Percentage variation in power dissipation

after fatigue test in comparison with that

before fatigue test

% +/-40 (Maximum)

Bundle spacer for line for ACSR BISON Conductor (for twin bundle conductor only)


1. Type of Bundle Spacer Armour grip type

2. Insert Main body Retaining

rods (if any)

(i) Materials of components

Aluminu

m alloy

6061/650

32

Tube

Aluminum

alloy

6063/63400;

6061/65032

Aluminum

alloy

6061/65032

(ii) Manufacturing process of component parts

Forged Tube-

extrusion

Heat

treatment

during

manufacturi

ng

3. Retaining rods (if used)

(a) Number of retaining rods used for

each spacer

no. 8

(b) Diameter mm 7.87 ± 0.1

(c) Length mm 1100+15

4. Elastomer

(a) Type Chloroprene/Neoprene

(c) Moulded on insert Yes

(d) Shore hardness 65 to 80

(e) Thickness on insert mm 5(Average)

(f) Temp. range for which designed °C 95

5. Minimum ultimate tensile strength of spacer

(a) Compressive load kN 14

(b) Tensile load kN 7



31

6. Slipping strength of spacer clamp

a) Before vibration test KN 2.5

b) After vibration test KN 2



kV 154

8. Maximum Radio Interference Voltage

(RIV) at 1 MHz for phase to earth voltage

of 154 kV (rms) under dry condition

Micro

volts

1000

Rigid spacer for jumper for ACSR BISON Conductor (for Twin bundle conductor)


1. Type of Spacer Rigid type without retaining

rods

2. Material of component parts

(a) Clamp Aluminum alloy (4600)

(b) Main body Aluminum alloy 6063/63400

3. Manufacturing process of component parts

(a) Clamp Die-casting

(b) Main body Aluminum extrusion

4. Minimum ultimate tensile strength of spacer

(a) Compressive load kN 14

(b) Tensile load kN 7.0

5. Slipping strength of spacer clamp kN 2.5

6. Maximum Magnetic power loss per spacer for 600

Amps, 50 Hz Alternating Current Watts 1

7. Minimum corona Extinction voltage kV (rms)

under dry condition

kV 154

8. Maximum Radio Interference Voltage (RIV) at 1

MHz for phase to earth voltage of 154 kV (rms)

under dry condition

Micro

volts

1000



32


5.1 Type Tests

5.1.1 On the complete Insulator String with Hardware Fittings

Tests Ref Strings on which

test to be

conducted*.

a) Power frequency voltage withstand test with

corona control rings/grading ring and arcing

horns under wet condition

: As per

IEC:60383

SIS (T), DT(T),

SISP

b) Impulse voltage withstand test under dry

condition : As per

IEC:60383

SIS (T), DT(T),

SISP

c) Voltage distribution test (in case of Disc

Insulators only) : As per

Annex-A

SIS (T), DT(T),

SISP

d) Mechanical Strength test : As per

Annex-A

SIS (T), DT(T),

SISP

e) Vibration test : As per

Annex-A SIS (T), DT(T)

SIS(T) : Single I Suspension with Twin Bison Conductor, DT(T) : Double Tension with

Twin Bison Conductor, SIS P: Single I Suspension Pilot with Twin Bison Conductor

5.1.2 On Suspension Hardware Fittings only

(a) Visual examination & Dimensional and

material Verification

IEC:61284; Clause 7 & 8

(b) Magnetic power loss test for suspension

assembly

Annexure-A

(c) Clamp slip strength Vs torque test for

suspension clamp

IEC:61284; Clause 11.4.2

(d) Vertical damage load & Failure load test

for suspension clamp

IEC:61284; Clause 11.4.1

(e) OZONE resistance Test on elastomer IEC:61854

5.1.3 On Tension Hardware fittings only



IEC:61284; Clause 7 & 8

(b) Heat cycle test for dead end Assembly IEC:61284; Clause 13.0

(c) Mechanical Damage & Failure load Test IEC:61284; Clause 11.5.2



33

(excluding clamp)

(d) Tensile test for dead-end clamp IEC:61284; Clause 11.5.1

5.1.4 Mid Span Compression Joint for Conductor and Earth wire



IEC:61284; Clause 7 & 8

(b) Heat cycle test IEC:61284;

(c) Tensile test IEC:61284; Clause 11.5.1

NOTE : ‘Heat cycle’, ‘tests are not applicable to Mid span compression joint for

Earthwire

5.1.5 T-Connector for Conductor



IEC:61284; Clause 7 & 8

(b) Heat cycle test IEC:61284;

(c) Tensile test IEC:61284; Clause 11.6.2

(d) Axial tensile load test on welded portion Annexure - A

5.1.6 Repair Sleeve for Conductor



IEC:61284; Clause 7 & 8

(b) Tensile test IEC:61284; Clause 11.6.1

5.1.7 Flexible Copper Bond


material verification

IEC:61284; Clause 7 & 8

(b) Slip Strength Test Annexure – A

5.1.8 Vibration Damper for Conductor & Earth wire



IEC:61897; Clause 7.1 &

7.2

(b) Dynamic characteristics test Annexure – A

(c) Vibration analysis Annexure – A

(d) Clamp slip test IEC:61897; Clause 7.5

(e) Clamp bolt tightening test IEC:61897; Clause 7.7

(f) Attachment of weights to messenger

cable

IEC:61897; Clause 7.8



34

(g) Attachment of clamp to messenger cable IEC:61897; Clause 7.8

(h) Fatigue tests Annexure - A

(i) Magnetic power loss test Annexure - A

(j) Damper effective evaluation IEC:61897; Cl 7.11.3.2

NOTE : Magnetic Power Loss is not applicable to Vibration damper forEarthwire

5.1.9 Spacer / Rigid Spacer for Jumper

(a) Visual examination & verification of

dimension, materials and mass

IEC:61854; Clause 7.1 &

7.2

(b) Clamp slip test Annexure – A

(c) Clamp bolt tightening test (if applicable) IEC:61854; Clause 7.5.3

(d) Vibration Test

(i) Vertical Vibration Annexure – A

(ii) Longitudinal Vibration Annexure – A

(iii) Sub span Oscillation Annexure – A

(e) Magnetic power loss test (if applicable) Annexure – A

(f) Compression & Tension test Annexure – A

(g) Corona extinction voltage test (dry) Annexure - A

(h) Radio interference voltage test (dry) Annexure – A

(i) Ozone Resistance test on Elastomer IEC:61854; Clause 7.6.3

NOTE : ‘Vibration Test’ & ‘Ozone Test’ are not applicable to Rigid Spacers.

5.1.10 Earth wire Suspension Clamp Assembly

(a) Visual examination & Dimensional

and material Verification

IEC:61284

(b) Vertical Damage load & failure load

test (excluding clamp)

IEC:61284; Cl 11.4.1 & 11.4.2

(c) Clamp Slip test for suspension

clamp

IEC:61284; Cl 11.4.1 & 11.4.2

5.1.11 Earth wire Tension Clamp Assembly



IEC:61284

(b) Mechanical Damage & failure load


IEC:61284; Cl 11.5.1 & 11.5.2

(c) Clamp Slip test for suspension

clamp

IEC:61284; Cl 11.5.1 & 11.5.2

5.1.12 Type tests specified under Clause 5.1.1 to 5.1.11 shall not be required to be

carried out if a valid test certificate is available for a similar design, i.e., tests



35

conducted earlier should have been conducted in accredited laboratory

(accredited based on ISO/IEC guide 25/17025 or EN 45001 by the National

Accreditation body of the country where laboratory is located) or witnessed

by the representative (s) of any Utility.

In the event of any discrepancy in the test report (i.e., any test report not

applicable due to any design / material/manufacturing process change

including substitution of components or due to non compliance with the

requirement stipulated in the Technical Specification) the tests shall be

conducted by the Contractor at no extra cost to the Employer/ Employer/

Purchaser.

5.2 Acceptance Tests

5.2.1 On Both Suspension and Tension Hardware Fittings



IEC:61284; Clause 7 & 8

(b) Galvanising/Electroplating test Annexure-A

(c) Mechanical damage and failure

load test of each component (excluding )

corona control rings grading )

ring and arcing horn)

IEC:61284 Clause 11.3.1

(d) Mechanical Strength test of welded joint Annexure-A

(e) Mechanical strength test for corona

control rings,/ grading ring and arcing

horn

BS:3288- (Part-I), Clause

7.3.2

(f) Test on locking device for ball and socket

coupling

IEC:60372 (2)

(g) Chemical analysis, hardness tests, grain

size, inclusion rating & magnetic particle

inspection for forgings/castings

Annexure - A

5.2.2 On Suspension Hardware Fitting only

(a) Clamp Slip test for suspension clamp

Annexure-A (b) Shore hardness test of elastomer cushion

for AG suspension clamp

(c) Bend test for armour rod set IS:2121-(Part-I), Clause

7.5, 7.10, 7.11 (d) Resilience test for armour rod set

(e) Conductivity test for armour rods set

5.2.3 On Tension Hardware Fittings Only

(a) Tensile test for dead end assembly IEC:61284 Clause 11.5.1



36

5.2.4 Mid Span Compression Joint for Conductor and Earth wire



IEC:61284; Clause 7 & 8

(b) Galvanising test Annexure - B

(c) Hardness test Annexure - B

5.2.5 T-Connector for Conductor



IEC:61284; Clause 7 & 8


(c) Axial tensile load test for welded portion Annexure-A

5.2.6 Repair Sleeve for Conductor



IEC:61284; Clause 7 & 8


5.2.7 Flexible Copper Bond



IEC:61284; Clause 7 & 8

(b) Slip Strength Test Annexure – A

5.2.8 Vibration Damper for Conductor and Earthwire



IEC:61897; Clause 7.1 &

7.2

(b) Galvanising test IEC:61897; Clause 7.3

(i) On damper masses

(ii) On messenger cable

(c) Clamp slip test IEC:61897; Clause 7.5

(d) Clamp bolt tightening test IEC:61897; Clause 7.7

(e) Attachment of weights to messenger

cable

IEC:61897; Clause 7.8

(f) Attachment of clamp to messenger cable IEC:61897; Clause 7.8

(g) Verification of resonance frequencies Annexure – B

(h) Strength of messenger cable Annexure – B

(i) Dynamic characteristics test Annexure – B



37

5.2.9 Spacer Damper for Conductor/Spacer/Rigid Spacer

(a) Visual examination & verification of

dimension, materials and mass

IEC:61854; Clause 7.1 &

7.2

(b) Galvanising test Annexure – A

(c) Movement test (except for spacers for

jumpers)

Annexure – A

(d) Clamp slip test Annexure – A

(e) Clamp bolt tightening test (if applicable) IEC:61854; Clause 7.5.3

(f) Compression and tension test Annexure – A

(g) Assembly torque test Annexure – B

(h) Hardness test for elastomer(if applicable) Annexure – B

(i) UTS of retaining rods ( if applicable) Annexure – B

5.2.10 Earth wire Suspension Clamp Assembly



IEC:61284


(c) Vertical Damage load & failure load


IEC:61284; Cl 11.4.1 & 11.4.2

(d) Clamp Slip test for suspension

clamp

IEC:61284; Cl 11.4.1 & 11.4.2

5.2.11 Earth wire Tension Clamp Assembly



IEC:61284


(c) Mechanical Damage & failure load


IEC:61284; Cl 11.5.1 & 11.5.2

(d) Clamp Slip test for suspension

clamp

IEC:61284; Cl 11.5.1 & 11.5.2

5.3 Routine Tests

5.3.1 For Hardware Fittings

a) Visual examination IS:2486-(Part-I)

b) Proof Load Test : As per Annexure-A



38

5.3.1 For conductor and earthwire accessories

a) Visual examination and

dimensional verification

: As per IS:2121(Part-II)

Clause 6.2, 6.3 7 6.7

5.4 Tests During Manufacture on all components as applicable

a) Chemical analysis of Zinc used for galvanising IS:2486-(Part-I)

b) Chemical analysis mechanical metallographic

test and magnetic particle inspection for

malleable castings

: As per Annexure-A

c) Chemical analysis, hardness tests and magnetic

particle inspection for forging

: As per Annexure-A


5.5.1 As indicated in clause 5.1.12 no type test charges shall be payable.

5.5.2 In case type testing is required due to non availability of type test reports,

for type test on the complete insulator string, the Contractor has to arrange

similar insulators at his own cost.

5.5.3 Bidder shall indicate the laboratories in which they propose to conduct the

type tests. They shall ensure that adequate facilities for conducting the tests

are available in the laboratory and the tests can be completed in these

laboratories within the time schedule guaranteed by them in the appropriate

schedule.

5.5.4 The entire cost of testing for acceptance and routine tests and tests during

manufacture specified herein shall be treated as included in the quoted Ex-

works/CIF Price.

5.5.5 In case of failure in any type test, repeat type tests are required to be

conducted, then, all the expenses for deputation of Inspector/Employer's

representative shall be deducted from the contract price. Also if on receipt of

the Contractor's notice of testing, the Employer's representative/Inspector

does not find 'plant' to be ready for testing the expenses incurred by the

Employer for re-deputation shall be deducted from contract price.

5.5.6 The Contractor shall intimate the Employer about carrying out of the type

tests along with detailed testing programme at least 3 weeks in advance (in

case of Domestic Contractor and at least 6 weeks advance in case of Foreign

Contractor) of the scheduled date of testing during which the Employer will



39

arrange to depute his representative to be present at the time of carrying out

the tests.

5.6 Sample Batch For Type Testing

5.6.1 The Contractor shall offer material for sample selection for type testing only

after getting Quality Assurance Programme approved by the Employer. The

Contractor shall offer at least three times the quantity of materials required

for conducting all the type tests for sample selection. The sample for type

testing will be manufactured strictly in accordance with the Quality

Assurance Programme approved by the Employer.

5.6.2 Before sample selection for type testing the Contractor shall be required to

conduct all the acceptance tests successfully in presence of Employer 's

representative.

5.7 Schedule of Testing and Additional Tests

5.7.1 The Bidder has to indicate the schedule of following activities in their bids

(a) Submission of drawing for approval.

(b) Submission of Quality Assurance programme for approval.

(c) Offering of material for sample selection for type tests.

(d) Type testing.

5.7.2 The Employer reserves the right of having at his own expense any other

test(s) of reasonable nature carried out at Contractor’s premises, at site, or in

any other place in addition to the aforesaid type, acceptance and routine

tests to satisfy himself that the material comply with the specifications.

5.7.3 The Employer also reserves the right to conduct all the tests mentioned in

this specification at his own expense on the samples drawn from the site at

Contractor’s premises or at any other test center. In case of evidence of non

compliance, it shall be binding on the part of Contractor to prove the

compliance of the items to the technical specifications by repeat tests, or

correction of deficiencies, or replacement of defective items, all without any

extra cost to the Employer.

5.8 Test Reports

5.9.1 Copies of type test reports shall be furnished in at least six copies along with

one original. One copy shall be returned duly certified by the Employer,

only after which the commercial production of the concerned material shall

start.



40

5.9.2 Copies of acceptance test report shall be furnished in at least six copies. One

copy shall be returned, duly certified by the Employer, only after which the

materials will be despatched.

5.9.3 Record of routine test report shall be maintained by the Contractor at his

works for periodic inspection by the Employer 's representative.

5.9.4 Test certificates of tests during manufacture shall be maintained by the

Contractor. These shall be produced for verification as and when desired by

the Employer.

5.10 Inspection

5.10.1 The Employer 's representative shall at all times be entitled to have access to

the works and all places of manufacture, where the material and/or its

component parts shall be manufactured and the representatives shall have

full facilities for unrestricted inspection of the Contractor’s, sub-Contractor’s

works raw materials. manufacturer’s of all the material and for conducting

necessary tests as detailed herein.

5.10.2 The material for final inspection shall be offered by the Contractor only

under packed condition as detailed in clause 5.11 of this part of the

Specification. The engineer shall select samples at random from the packed

lot for carrying out acceptance tests.

5.10.3 The Contractor shall keep the Employer informed in advance of the time of

starting and of the progress of manufacture of material in its various stages

so that arrangements could be made for inspection.

5.10.4 Material shall not be dispatched from its point of manufacture before it has

been satisfactorily inspected and tested unless the inspection is waived off

by the Employer in writing. In the latter case also the material shall be

dispatched only after all tests specified herein have been satisfactorily

completed.

5.10.5 The acceptance of any quantity of material shall in no way relieve the

Contractor of his responsibility for meeting all the requirements of the

Specification, and shall not prevent subsequent rejection, if such material is


5.11 Packing and Marking

5.11.1 All material shall be packed in strong and weather resistant wooden

cases/crates. The gross weight of the packing shall not normally exceed 200

Kg to avoid handling problems.

5.11.2 The packing shall be of sufficient strength to withstand rough handling

during transit, storage at site and subsequent handling in the field.



41

5.11.3 Suitable cushioning, protective padding, dunnage or spacers shall be

provided to prevent damage or deformation during transit and handling.

5.11.4 Bolts, nuts, washers, cotter pins, security clips and split pins etc. shall be

packed duly installed and assembled with the respective parts and suitable

measures shall be used to prevent their loss.

5.11.5 Each component of Hardware fittings and accessories shall be legibly and

indelibly marked with trade mark of the manufacturer. However, in such

type of component/item, which consists of many parts and are being

supplied in assembled condition( suspension clamp, vibration damper,

spacer/rigid spacer, spacer damper etc.), the complete assembly shall be

legibly and indelibly marked on main body/on one of the parts. The symbol

/ alongwith the word ‘TOP’ shall be marked on the main body of the

spacer damper for installing spacer damper in correct position.

5.11.6 All the packing cases shall be marked legibly and correctly so as to ensure

safe arrival at their destination and to avoid the possibility of goods being

lost or wrongly dispatched on account of faulty packing and faulty or

illegible markings. Each wooden case/crate shall have all the markings

stenciled on it in indelible ink.

5.12 Standards

5.12.1 The Hardware fittings; conductor and earth wire accessories shall conform

to the following Indian/International Standards which shall mean latest

revisions, with amendments / changes adopted and published, unless

specifically stated otherwise in the Specification.

5.12.2 In the event of the supply of hardware fittings; conductor and earth wire

accessories conforming to standards other than specified, the Bidder shall

confirm in his bid that these standards are equivalent to those specified. In

case of award, salient features of comparison between the Standards

proposed by the Contractor and those specified in this document will be

provided by the Contractor to establish their equivalence.

Sl.

No.

Indian Standard Title International

Standard

1. IS: 209-1992 Specification for zinc BS:3436-1986

2. IS:398-1992

Part-V

Aluminum Conductor Galvanised Steel-


KV) and above

IEC:1089-1991

BS:215-1970

3. IS 1573 Electroplated Coating of Zinc on iron and

Steel

4. IS : 2121 (Part-II) Specification for Conductor and



42

Earthwire Accessories for Overhead

Power lines:

Mid-span Joints and Repair Sleeves for

Conductors

5. IS:2486 (Part-I) Specification for Insulator Fittings for

Overhead power Lines with Nominal

Voltage greater than 1000 V:

General Requirements and Tests

6. IS:2629 Recommended Practice for Hot Dip


7. IS:2633 Method of Testing Uniformity of Coating


8. Ozone test on Elastomer ASTM- D1 171

9. Tests on insulators of Ceramic material or

glass for overhead lines with a nominal

voltage greater than 1000V

IEC:383-1993

10. IS:4826 Galvanised Coating on Round Steel

Wires

ASTM A472-729

BS:443-1969

11. IS:6745 Methods of Determination of Weight of


Steel Articles

BS:433

ISO : 1460 (E)

12. IS:8263 Method of Radio Interference Tests on


IEC:437

NEMA:107

CISPR

13. IS:6639 Hexagonal Bolts for Steel Structures ISO/R-272

14. IS:9708 Specification for Stock Bridge Vibration

Dampers for Overhead Power Lines

15. IS:10162 Specification for Spacers Dampers for

Twin Horizontal Bundle Conductors



43



Name and Address




N - 19-ND

UK




1 Rue de verembe,

Geneva

SWITZERLAND


Manak Bhavan,


New Delhi - 110001.

INDIA

ISO International Organisation for Standardization.



Aurehoegvej-12

DK-2900, Heeleprup,

DENMARK.



New York, NY 10017

U.S.A.



44

ANNEXURE - A

1.0 Tests on Complete Strings with Hardware Fittings

1.1 Voltage Distribution Test (For Insulator String with Disc Insulators)

The voltage across each insulator unit shall be measured by sphere gap

method. The result obtained shall be converted into percentage. The voltage

across any disc shall not exceed the values specified in the Standard

Technical Particulars.


The sample when subjected to power frequency voltage shall have a corona

extinction voltage of not less than that stipulated in the Standard Technical

Particulars. There shall be no evidence of corona on any part of the sample.

The test shall be carried out as per IEC:61284. The atmospheric condition

during testing shall be recorded and the test results shall be accordingly

corrected with suitable correction factor as stipulated in IEC 60060-1.

1.3 Radio Interference Voltage Test (Dry)

Under the conditions as specified under (1.2) above, the sample shall have a

radio interference voltage level below that stipulated in the Standard

Technical Particulars. The test procedure shall be in accordance with

IEC.61284

1.4 Mechanical Strength Test

The complete insulator string along with its hardware fitting excluding

arcing horn, corona control ring, grading ring and suspension

assembly/dead end assembly shall be subjected to a load equal to 50% of the

specified minimum ultimate tensile strength (UTS) which shall be increased

at a steady rate to 67% of the minimum UTS specified. The load shall be

held for five minutes and then removed. After removal of the load, the

string components shall not show any visual deformation and it shall be

possible to disassemble them by hand. Hand tools may be used to remove

cotter pins and loosen the nuts initially. The string shall then be

reassembled and loaded to 50% of UTS and the load shall be further

increased at a steady rate till the specified minimum UTS and held for one

minute. No fracture should occur during this period. The applied load shall

then be increased until the failing load is reached and the value recorded.

1.5 Vibration Test

The suspension string shall be tested in suspension mode, and tension string

in tension mode itself in laboratory span of minimum 30 meters. In the case



45

of suspension string a load equal to 600 kg shall be applied along the axis of

the suspension string by means of turn buckle. The insulator string along

with hardware fittings and sub conductors each tensioned at 25% of UTS

shall be secured with clamps. The system shall be suitable to maintain

constant tension on each sub-conductors throughout the duration of the test.

Vibration dampers shall not be used on the test span. Both the sub-

conductors shall be vertically vibrated simultaneously at one of the

resonance frequencies of the insulators string (more than 10 Hz) by means

of vibration inducing equipment. The peak to peak displacement in mm of

vibration at the antinode point nearest to the string shall be measured and

the same shall not be less than 1000/f1.8 where f is the frequency of

vibration in cycles/sec. The insulator string shall be vibrated for not less than

10 million cycles without any failure. After the test the disc insulators shall

be examined for looseness of pins and cap or any crack in the cement. The

hardware shall be examined for looseness, fatigue failure and mechanical

strength test. There shall be no deterioration of properties of hardware

components and disc insulators after the vibration test. The disc insulators

shall be subjected to the following, tests as per relevant standards :

Sl.No. Test Percentage of

insulator units to

be tested

a) Temperature cycle test followed by

mechanical performance test

60

b) Puncture test / steep wave front test (Only

for glass insulators)

40

1.6 Power Arc test

This test shall be performed on the complete string in accordance with IEC

Technical Report IEC : 61467-1997 with the following test series :

Test circuit Short circuit current Number and duration of test

B In = Isys = 40 KA Two of tn = 0.2s and

one of tn = 0.5s

The acceptance criteria after the completion of test series shall be following.

a) Insulator separation not permitted.

b) Burning/melting of metal components, breaking of insulator sheds,

glaze removal are permitted.



46

c) The complete insulator string along with its hardware fittings

including arcing horn, corona control ring/grading ring shall

withstand 80% of UTS.

1.7 Assembly Test

This test shall be carried out to ensure that the cotter pins, bolts, clamps etc.,

fit freely and properly.

2.0 Tests on Hardware Fittings

2.1 Magnetic Power Loss Test for Suspension Assembly

The sample shall be tested in a manner to simulate service conditions for 50

Hz pure sine-wave. This test shall be carried out as per Clause 12.0 of

IEC:61284. An alternating current over the range of 400 to 600 Amps (per

subconductor), shall be passed through a suitable length of conductor and

the power losses shall be measured both with and without the fittings

assembled on the conductor. Armour rods shall be applied to the conductor

if they are used in service. The reading of the wattmeter with and without

five suspension clamps shall be recorded. The test is passed if the average

power loss for suspension clamp at given ampere is less than or equal to the

value indicated in the Standard Technical Particulars.

2.2 Galvanising/Electroplating Test

The test shall be carried out as per Clause no. 5.9 of IS:2486-(Part-1) except

that both uniformity of zinc coating and standard preecee test shall be

carried out and the results obtained shall satisfy the requirements of this

specification.

2.3 Mechanical Strength Test of Welded Joint

The welded portion of the component shall be subjected to a Load of 2000

kgs for one minute. Thereafter, it shall be subjected to die-

penetration/ultrasonic test. There shall not be any crack at the welded

portion.

2.4 Shore Hardness Test for Elastomer Cushion for AG Suspension Assembly

The shore hardness at various points on the surface of the elastomer cushion

shall be measured by a shore hardness meter and the shore hardness

number shall be between the values indicated in the Standard Technical

Particulars.

2.5 Proof Load Test

Each component shall be subjected to a load equal to 50% of the specified

minimum ultimate tensile strength which shall be increased at a steady rate



47

to 67% of the UTS specified. The load shall be held for one minute and then

removed. After removal of the load the component shall not show any

visual deformation.

2.6 Tests for Forging Casting and Fabricated Hardware

The chemical analysis, hardness test, grain size, inclusion rating and

magnetic particle inspection for forging, castings and chemical analysis and

proof load test for fabricated hardware shall be as per the internationally

recognised procedures for these tests. The sampling will be based on heat

number and heat treatment batch. The details regarding test will be as in the

Quality Assurance programme.

3.0 Tests on Conductor and Earth wire Accessories

3.1 T-Connector for Conductor

Axial Tensile Load Test for Welded Portion

The sleeve portion of the T-Connector shall be compressed on conductor.

The compressed portion shall be held rigidly on some fixtures and axial load

shall be applied along with the jumper terminal The load shall be increased

gradually till breaking of welded joint occurs. The breaking load should be

above the value indicated in the Standard Technical Particulars.

3.2 Flexible Copper Bond

Slip Strength Test

On applying a load of 3 kN between the two ends, stranded flexible copper

cable shall not come out of the connecting lugs and none of its strands shall

be damaged. After the test, the lugs shall be cut open to ascertain that the

gripping of cable has not been affected.

3.3 Vibration Damper for Conductor and Earth wire

(a) Damper Characteristics Test

The damper shall be mounted with its clamp tightened with torque

recommended by the manufacturer on shaker table capable of

simulating sinusoidal vibrations for aeolian vibration frequency

band ranging from 0.18/d to 1.4/d-where d is the conductor diameter

in meters. The damper assembly shall be vibrated vertically with a +

1 mm amplitude upto 15 Hz frequency and beyond 15 Hz at ± 0.5mm

to determine following characteristics with the help of suitable

recording instruments:

(i) Force Vs frequency



48

(ii) Phase angle Vs frequency

(iii) Power dissipation Vs frequency

The Force Vs frequency curve shall not show steep peaks at

resonance frequencies and deep troughs between the resonance

frequencies. The resonance frequencies shall be suitably spread

within the aeolian vibration frequency-band between the lower and

upper dangerous frequency, limits determined by the vibration

analysis of conductor/earth wire without dampers.

Acceptance criteria for vibration damper.

(i) The above dynamic characteristics test on five damper shall

be conducted.

(ii) The mean reactance and phase angle Vs frequency curves

shall be drawn with the criteria of best fit method.

(iii) The above mean reactance response curve should lie within

the limits specified for ACSR BISON conductor & 3.35 mm

Earthwire

(iv) The above mean phase angle response curve shall be between

25o to 130o within the frequency range of interest.

(v) If the above curve lies within the envelope, the damper

design shall be considered to have successfully met the

requirement.

(vi) Visual resonance frequencies of each mass of damper is to be

recorded and to be compared with the guaranteed values.

(b) Vibration Analysis

The vibration analysis of the conductor/earthwire shall be done with

and without damper installed on the span. The vibration analysis

shall be done on a digital computer using energy balance approach.

The following parameters shall be taken into account for the purpose

of analysis :

(i) The analysis shall be borne for single conductor/earthwire

without armour rods as per the parameters given under

clause 2.5.13 and 3.3.8 of this part of the Specification. The

tension shall be taken as 25% of RTS of conductor/ earth wire

for a span ranging from 100 m to 1100 m.

(ii) The self damping factor and flexural stiffness (El) for

conductor and earthwire shall be calculated on the basis of



49

experimental results. The details of experimental analysis

with these data should be furnished.

(iii) The power dissipation curve obtained from Damper

Characteristics Test shall be used for analysis with damper.

(iv) Examine the aeolian vibration level of the

conductor/earthwire with and without vibration damper

installed at the recommended location or wind velocity

ranging from 0 to 30 Km per hour, predicting amplitude,

frequency and vibration energy input.

(v) From vibration analysis of conductor/earthwire without

damper, antinode vibration amplitude and dynamic strain

levels at clamped span extremities as well as antinodes shall

be examined and thus lower and upper dangerous frequency

limits between which the aeolian vibration levels exceed the

specified limits shall be determined.

(vi) From vibration analysis of conductor/earthwire with

damper/dampers installed at the recommended location, the

dynamic strain level, at the clamped span extremities,

damper attachment point and the antinodes on the

conductor/earthwire shall be determined. In addition to

above damper clamp vibration amplitude and antinode

vibration amplitudes shall also be examined.

The dynamic strain levels at damper attachment points,

clamped span extremities and antinodes shall not exceed the

specified limits. The damper vibration amplitude shall not be

more than that of the specified fatigue limits.

c) Fatigue Tests

(i) Test Set Up

The fatigue tests shall be conducted on a laboratory set up

with a minimum effective span length of 30 m. The

conductor/earthwire shall be tensioned at 25% of RTS of

conductor/earthwire and shall not be equipped with

protective armour rods at any point. Constant tension shall be

maintained within the span by means of lever arm

arrangement. After the conductor/earthwire has been

tensioned, clamps shall be installed to support the

conductor/earthwire at both ends and thus influence of

connecting hardware fittings are eliminated from the free



50

span. The clamps shall not be used for holding the tension on

the conductor/earthwire. There shall be no loose parts, such

as suspension clamps, U bolts on the test span supported

between clamps mentioned above. The span shall be

equipped with vibration inducing equipment suitable for

producing steady standing vibration. The inducing

equipment shall have facilities for stepless speed control as

well as stepless amplitude arrangement. Equipment shall be

available for measuring the frequency, cumulative number of

cycles and amplitude of vibration at any point along the span.

(ii) Fatigue Test

The vibration damper shall be installed on the test span with

the manufacturer’s specified tightening torque. It shall be

ensured that the damper shall be kept minimum three loops

away from the shaker to eliminate stray signals influencing

damper movement.

The damper shall then be vibrated at the highest resonant

frequency of each damper mass. For dampers involving

torsional resonant frequencies, tests shall be done at torsional

modes also in addition to the highest resonant frequencies at

vertical modes. The resonance frequency shall be identified as

the frequency at which each damper mass vibrates with the

maximum amplitude on itself. The amplitude of vibration of

the damper clamp shall be maintained not less than ± 25/f

mm, where f is the frequency in Hz.

The test shall be conducted for minimum ten million cycles at

each resonant frequency mentioned above. During the, test if

resonance shift is observed the test frequency shall be tuned

to the new resonant frequency.

The clamp slip test as mentioned hereinabove shall be

repeated after fatigue test without retorquing or adjusting the

damper clamp, and the clamp shall withstand a minimum

load equal to 80% of the slip strength for a minimum

duration of one minute.

After the above tests, the damper shall be removed from

conductor / earthwire and subjected to damper characteristics

test. There shall not be any major deterioration in the

characteristic of the damper. The damper then shall be cut



51

open and inspected. There shall not be any broken, loose, or

damaged part. There shall not be significant deterioration or

wear of the damper. The conductor/earthwire under clamp

shall also be free from any damage.

For the purpose of acceptance, the following criteria shall be

applied.

(1) There shall not be any resonant frequency shift before

and after the test by more than + 20 %.

(2) The power dissipation of the damper before and after

test at the individual resonant frequencies do not

differ by more than + 20 %.

3.4 Spacer (for twin bundle)

(a) Vibration Tests

The test set up shall be as per Clause No.3.3(c) (i) of Annexure - A.

The spacer assembly shall be clamped to conductor. During the

vibration tests the axis of the clamp of sample shall be maintained

parallel to its initial static position by applying a tension of 25% of

RTS of conductor. The spacer assembly shall be free to vibrate and

shall not be retorqued or adjusted between the tests.

All the vibration tests mentioned hereunder shall be conducted on

the same sample on the same test span. The samples shall withstand

the vibration tests without slipping on the conductor. loosening,

damage or failure of component parts. After each vibration test,

clamp slip test shall be carried out as per the procedure given in

Clause No3.5 (b) below

(i) Longitudinal Vibration Test

The stationary conductor and the vibrating conductor/equivalent

diameter of aluminium alloy tube shall be restrained by fixed

clamps. The displacement of the vibrating conductor shall be 25mm

minimum on either side. The longitudinal movement shall be

parallel to the conductor at frequency not less than 2 Hz for

minimum one million cycles.

(ii) Vertical Vibration Test

The spacer/spacer damper shall be installed in the middle of the test

span and the frequency chosen so as to get an odd number of loops.



52

The shaker shall be positioned at least two loops away from the test

specimen to allow free movement of the conductor close to the test

specimen. One conductor shall be connected to the shaker and

vibrated to an amplitude such that.

f1.8 Ymax > 1000 mm/sec.

Where Ymax being the antinode displacement (mm) and f is the test

frequency (Hz). The test frequency shall be greater than 24 Hz and

the total number of cycles shall be more than 10 millions.

(iii) Sub-span Oscillation Test

The test shall be conducted for oscillation in horizontal plane at

frequency higher than 3 Hz for minimum one million cycles. The

amplitude for oscillation shall be kept equivalent to an amplitude of

150 mm for a full sub-span of 80m. Both the conductor shall be

vibrated 180 deg. out of phase with the above minimum amplitude.

3.5 Magnetic Power Loss Test for Damper/Spacer

The sample involving ferrous parts shall be tested in a manner to simulate

service conditions for 50 Hz pure sine-wave. The test should be carried out

at various currents ranging from 400 amperes to 800 amperes. The test shall

be carried out as per clause 12.0 of IEC:61284. The average power loss shall

be limited to the values indicated in the Standard Technical Particulars.


The sample when subjected to power frequency voltage shall have a corona

extinction voltage of not less than that indicated in the Standard Technical

Particulars. There shall be no evidence of corona on any part of the sample.

The test shall be carried out as per IEC:61284. The atmospheric condition

during testing shall be recorded and the test results shall be accordingly

corrected with suitable correction factor as stipulated in IEC 60060-1.

3.7 Radio Interference Voltage Test (Dry)

Under the conditions as specified under (3.7) above, the sample shall have a

radio interference voltage level below the value indicated in the Standard

Technical Particulars.. The test procedure shall be in accordance with

IEC.61284

3.8 Chemical Analysis Test



53

Chemical analysis of the material used for manufacture of items shall be

conducted to check the conformity of the same with Technical Specification

and approved drawing.

4.0 Tests on All components (As applicable)

4.1 Chemical Analysis of Zinc used for Galvanizing

Samples taken from the zinc ingot shall be chemically analysed as per IS-

209-1979. The purity of zinc shall not be less than 99.95%.

4.2 Tests for Forgings

The chemical analysis hardness tests and magnetic particle inspection for

forgings, will be as per the internationally recognised procedures for these

tests. The, sampling will be based on heat number and heat treatment batch.

The details regarding test will be as discussed and mutually agreed to by the

Contractor and Purchaser in Quality Assurance Programme.

4.3 Tests on Castings

The chemical analysis, mechanical and metallographic tests and magnetic

particle inspection for castings will be as per the internationally recognised

procedures for these tests. The samplings will be based on heat number and

heat treatment batch. The details regarding test will be as discussed and

mutually agreed to by the Contractor and Purchaser in Quality Assurance

Programme.



54

ANNEXURE-B

Acceptance Tests

1 Mid Span Compression Joint for Conductor and Earthwire

(a) Hardness Test

The Brinnel hardness at various points on the steel sleeve of

conductor core and of the earthwire compression joint and tension

clamp shall be measured.

2. T-Connector for Conductor

(a) Axial Tensile Load Test for Welded Portion

Same as clause 3.1 of Annexure - A .

3. Flexible Copper Bond

(a) Slip Strength Test

Same as clause 3.2 of Annexure - A.

4. Vibration Damper for Conductor and Earthwire

(a) Verification of Resonance Frequencies

The damper shall be mounted on a shaker table and vibrate at

damper clamp displacement of +/-0.5 mm to determine the resonance

frequencies. The resonance shall be visually identified as the

frequency at which damper mass vibrates with maximum

displacement on itself. The resonance frequency thus identified shall

be compared with the guaranteed value. A tolerance of ± 1 Hz at a

frequency lower than 15 Hz and ± 2 Hz at a frequency higher than 15

Hz only shall be allowed.

(b) Strength of the Messenger Cable

The messenger cable shall be fixed in a suitable tensile testing

machine and the tensile load shall be gradually applied until yield

point is reached. Alternatively, each strand of message caste may be

fixed in a suitable tensile testing machine and the tensile load shall

be gradually applied until yield point is reached. In such a case, the

95% of yield strength of each wire shall be added to get the total

strength of the caste. The load shall be not less than the value

guaranteed by the Contractor

(c) Damper Characteristics Test



55

The test will be performed as acceptance test with the procedure

mentioned for type test with sampling mentioned below

Vibration Damper of - 1 Sample for 1000 Nos. & below

Conductor

- 3 Samples for lot above 1 000 &

up to 5000 nos.

- Additional 1 sample for every

additional 1500 pieces above

5000.

The acceptance criteria will be as follows

(i) The above dynamic characteristics curve for reactance &

phase angle will be done for frequency range of ranging from

0.18/d to 1.4/d-where d is the conductor diameter in meters.

The damper assembly shall be vibrated vertically with a + 1

mm amplitude upto 15 Hz frequency and beyond 15 Hz at ±

0.5mm

(ii) If all the individual curve for dampers are within the

envelope as already mentioned for type test for reactance &

phase angle, the lot passes the test.

(iii) If individual results do not fall within the envelope,

averaging of characteristics shall be done.

(a) Force of each damper corresponding to particular frequency

shall be taken & average force of three dampers at the

frequency calculated.

(b) Similar averaging shall be done for phase angle.

(c) Average force Vs frequency and average phase Vs frequency

curves shall be plotted on graph paper. Curves of best fit shall

be drawn for the entire frequency range.

(d) The above curves shall be within the envelope specified.

5. Spacer Damper / Spacer

(a) Test Set up

The test set up for the test described hereunder shall be as per clause

3.3 (c) (i) Annexure-A.

(b) Movement Test



56

The spacer assembly shall be capable of the following movements

without damaging the conductor, assuming one conductor is fixed

and the other moving :

(i) Longitudinal movement ± 50 mm

parallel to the conductor

(ii) Vertical movement in a ± 25 mm

vertical direction at right

angle to the conductor

(iii) Torsional movement/angular ± 5 deg.

movement in a vertical plane

parallel to the conductor

(c) Clamp Slip Test

Same as clause 3.5(b) of Annexure-A.

(d) Clamp Bolt Torque Test

The spacer assembly shall be attached to conductor. A torque of 150

per cent of the manufacturer's specified tightening torque shall be

applied to the clamp bolts or cap screws. There shall be no failure of

the component parts.

(e) Assembly Torque Test

The spacer assembly shall be installed on conductor. The same shall

not rotate on either clamp on applying a torque of 0.04 kN in

clockwise or anti-clockwise direction.

(f) Hardness test for Elastomer

The shore hardness at different points on the elastomer surface of

cushion grip clamp shall be measured by shore hardness meter. They

shall lie between the values indicated in the Standard Technical

Particulars.

(g) UTS of Retaining Rods

The ultimate tensile strength of the retaining rods shall be measured.

The value shall not be less than 35 kg/sq.mm.


SECTION–VIII Volume-II

1


SECTION - 8

1.0 Technical Description of Galvanised Steel Earth wire

1.1 Details of Earth wire

1.11 The galvanised steel earth wire shall generally conform to the specification of ACSR core wire as mentioned in IS: 398 (Part-II)-1976 except where otherwise specified herein.

1.1.2 The details of the earth wire for 220 kV are tabulated below:

a) Stranding and wire : 7/3.35 mm steel diameter

b) Number of strands

Steel core : 1

Outer steel layer : 6

c) Total sectional area : 61.7 sqmm.

Other technical details are furnished in the section–I of this Specification.

1.2 Workmanship

1.2.1 All steel strands shall be smooth, uniform and free from all imperfections, such as

spills and splits, die marks, scratches, abrasions and kinks after drawing and also

after stranding.

1.2.2 The finished material shall have minimum brittleness as it will be subjected to

appreciable vibration while in use.

1.2.3 The steel strands shall be hot dip galvanized and shall have minimum Zinc

coating after stranding, as stipulated in Cl. 2.0 of this section of the Specification.

The zinc coating shall be smooth, continuous, of uniform thickness, free from

imperfections. The steel wire rod shall be of such quality and purity that, when

drawn to the size of the strands specified and coated with zinc, the finished

strands shall be of uniform quality and have the same properties and

characteristics as prescribed in ASTM designation B498-M.

1.2.4 The steel strands shall be preformed and post formed in order to prevent

spreading of strands while cutting of composite earth wire. Care shall be taken to

avoid damage to galvanization during preforming and post-forming operation.

1.2.5 To avoid susceptibility towards wet storage stains (white rust), the finished

material shall be provided with a protective coating of boiled linseed oil.



2

1.3 Joints in Wires

There shall be no joint of any kind in the finished steel wire strand entering into

the manufacture of the earth wire. There shall be no strand joints or strand splices

in any length of the completed stranded earth wire.

1.4 Tolerances

The manufacturing tolerance to the extent of the limits as stipulated in Clause 2.0,

Table 1 of this section of the Specification only shall be permitted in the diameter

of the individual steel strands and lay length of the earth wire:

1.5 Materials

1.5.1 Steel

The steel wire strands shall be drawn from high carbon steel rods and the

chemical composition shall conform to the requirements as stipulated in Clause

2.0, Table 1 of this section of the Specification.

1.5.2 Zinc

The zinc used for galvanizing shall be electrolytic High Grade Zinc and shall

conform to the requirements of IS 209.

1.6 Standard Length

1.6.1 The standard length of the earth wire shall be as stipulated in Clause 2.0, Table 1

with the specified tolerance on standard length.

1.6.2 Random length will be accepted provided no length is less than 70% of standard

length and the total quantity of random lengths is not more than ten (10) percent

of the total quantity in each shipment.

2.0 Standard Technical Particulars

2.1 The standard Technical Particulars to be adhered by the contractor/ manufacturer

are furnished in Annexure-B if this section.


3.1 Type Tests on Earthwire

3.1.1 The required type tests on earthwire are stipulated hereunder. The specified type

tests under the following clause shall not be required to be carried out if a valid

test certificate is available for the same earthwire. The tests certificate shall be

considered valid if:



3

i. Tests conducted earlier is either conducted in accredited laboratory


accreditation body of the country where laboratory is located) or witnessed by the

representative(s) of any utility and

ii. Tests have been conducted not prior to 5 (five) years from the date of bid

opening.

In case the test have been conducted earlier than the above stipulated period or in

the event of any discrepancy in the test report (i.e., any test not applicable due to

any design/manufacturing change including substitution of components or due to

non-compliance with the requirement stipulated in the Technical Specifications),

the tests shall be conducted by the Supplier at no extra cost to the Purchaser.

3.1.2 The following tests are required on samples of earthwire from each

manufacturing works:-

a) UTS test : As per Annexure - A

b) DC resistance test : As per Annexure - A

3.2 Acceptance Tests on Earthwire

a) Visual and dimensional check on

drum

: As per Annexure - A

b) Visual check for joints scratches etc.

and lengths of earthwire


c) Dimensional check : As per Annexure - A

d) Lay length check : As per Annexure - A

e) Galvanising test : As per Annexure - A

f) Torsion test : As per Annexure - A

g) Elongation test : As per IS:398 (Part-II)

h) Wrap test : As per IS:398 (Part-II)

i) DC resistance test : As per IS:398 (Part-II)

j) Breaking load test : As per IS:398 (Part-II)

k) Chemical Analysis of steel : As per Annexure - A



4

3.3 Routine Tests on Earthwire

a) Check for correctness of stranding : As per Annexure - A

b) Check that there are no cuts, fins etc.

on the strands.


c) Check that drums are as per

Specification.


3.4 Tests During Manufacture Earthwire

a) Chemical analysis of zinc used for

galvanising


b) Chemical analysis of steel : As per Annexure - A


3.5.1 No type test charges shall be payable to the supplier.

3.5.2 Bidders shall indicate the laboratories in which they propose to conduct the

type tests. They shall ensure that the tests can be completed in these

laboratories within the time schedule guaranteed by them.

3.5.3 In case of failure in any type test the Contractor is either required to

manufacture fresh sample lot and repeat all the test successfully once or

repeat that particular type test three times successfully on the sample selected

from the already manufactured lot at his own expenses. In case fresh lot is

manufactured for testing then the lot already manufactured shall be rejected.

The decision of the Purchaser in this regard shall be final and binding on

Contractor.

3.5.4 The entire cost of testing for the acceptance and routine tests and tests during

manufacture specified herein shall be treated as included in the quoted unit

price except for the expenses of the inspector/ Employer’s representative.

3.5.5 In case of failure in any type test, repeat type tests are required to be

conducted, then all the expenses for deputation of Inspector/ Employer's

representative shall be deducted from the contract price. Also if on receipt of

the Contract's notice of testing the Employer's representative/Inspector does

not find ‘materials and facilities’ to be ready for testing, the expenses incurred

by the Employer for re-deputation shall be deducted from the contract price.



5


3.6.1 The Owner reserves the right of having at his own expenses any other test(s)

of reasonable nature carried out at Contractor’s premises, at site, or in any

other place in addition to the aforesaid type, acceptance and routine tests to

satisfy himself that the materials comply with the Specifications.

3.6.2 The Owner also reserves the right to conduct all the tests mentioned in this

specification at his own expense on the samples drawn from the site at

Contractor’s premises or at any other test center. In case of evidence of non

compliance, it shall be binding on the part of Contractor to prove the

compliance of the items to the technical specifications by repeat tests, or

correction of deficiencies, or replacement of defective item all without any

extra cost to the Owner.

3.7 Sample Batch for Type Testing

3.7.1 The Contractor shall offer material for selection of samples for type testing

only after getting Quality Assurance Plan approved from Owner’s Quality

Assurance Deptt. The sample shall be manufactured strictly in accordance

with the Quality Assurance Plan approved by Owner.

3.7.2 The Contractor shall offer at least three drums for selection of sample required

for conducting all the type test.

3.7.3 The Contractor is required to carry out all the Acceptance tests successfully in

presence of Owner’s representative before sample selection.

3.8 Test Reports

3.8.1 Copies of type test reports shall be furnished in at least six copies along with

one original. One copy will be returned duly certified by the Owner only after

which the commercial production of the material shall start.

3.8.2 Record of routine test reports shall be maintained by the Contractor at his

works for periodic inspection by the Owner's representative.

3.8.3 Test Certificates of tests during manufacture shall be maintained by the

Contractor. These shall be produced for verification as and when desired by

the Owner.

3.9 Inspection

3.9.1 The Owner 's representative shall at all times be entitled to have access to the

works and all places of manufacture, where earth wire shall be manufactured

and representative shall have full facilities for unrestricted inspection of the

Contractor’s works, raw materials and process of manufacture for conducting

necessary tests as detailed herein.



6

3.9.2 The Contractor shall keep the Owner informed in advance of the time of

starting and of the progress of manufacture of earth wire in its various stages

so that arrangements can be made for inspection.

3.9.3 No material shall be dispatched from its point of manufacture before it has

been satisfactorily inspected and tested, unless the inspection is waived off by

the Owner in writing. In the latter case also the earth wire shall be dispatched

only after satisfactory testing for all tests specified herein have been

completed.

3.9.4 The acceptance of any quantity of material shall in no way relieve the

Contractor of any of his responsibilities for meeting all requirements of the

Specification, and shall not prevent subsequent rejection if such material is


3.10 Test Facilities

3.10.1 The following additional test facilities shall be available at the Contractor’s

works :

a) Calibration of various testing and measuring equipment including

tensile testing machine, resistance measurement facilities, burette,

thermometer, barometer etc.

b) Standard resistance for calibration of resistance bridges.

c) Finished Earth wire shall be checked for length verification and

surface finish on separate rewinding machine at reduced speed

(variable from 8 to 16 meters per minute). The rewinding facilities

shall have appropriate clutch system and free of vibrations, jerks etc.,

with traverse laying facilities.

3.11 Packing for Earth wire

3.11.1 The Earth wire shall be supplied in non-returnable, strong, wooden drums

and provided with lagging of adequate strength, constructed to protect the

Earth wire against all damage and displacement during transit, storage and

subsequent handling and stringing operations in the field. The Contractor

shall be responsible for any loss or damage during transportation handling

and storage due to improper packing. The drums shall generally conform to

IS 778-1980, except as otherwise specified hereinafter.

3.11.2 The drums shall be suitable for wheel mounting and for letting off the earth

wire under a minimum controlled tension of the order of 5 kN

3.11.3 The general outline of the drum for Earth wire shall be as per annexed

drawing. The Contractor should submit their proposed drum drawings along

with the bid.



7

3.11.4 For Earth wire, two standard lengths shall be wound on each drum.

3.11.5 For Earth wire, each strand shall be individually welded to prevent parting of

two lengths at a tension less than 15 kN. The two ends where the first length

finishes and the second length starts, shall be clearly marked with adhesive

tape and no weld should be present outside these marks. The length between

the two marks shall be treated as scrap and will not be taken into account for

measurement purposes.

3.11.6 All wooden components shall be manufactured out of seasoned softwood free

from defects that may materially weaken the component parts of the drums.

Preservative treatment shall be applied to the entire drum with preservatives

of a quality which is not harmful to the earth wire.

3.11.7 The flanges shall be of two ply construction with each ply at right angles to

the adjacent ply and nailed together. The nails shall be driven from the inside

face flange, punched and then clenched on the outer face. The thickness of

each ply shall not vary by more than 3 mm from that indicated in the figure.

There shall be at least 3 nails per plank of ply with maximum nail spacing of

75 mm. Where a slot is cut in the flange to receive the inner end of the earth

wire the entrance shall be in line with the periphery of the barrel.

3.11.8 The wooden battens used for making the barrel of the earth wire shall be of

segmental type. These shall be nailed to the barrel supports with at least two

nails. The battens shall be closely butted and shall provide a round barrel with

smooth external surface. The edges of the battens shall be rounded or

chamfered to avoid damage to the earth wire.

3.11.9 Barrel studs shall be used for the construction of drums. The flanges shall be

holed and the barrel studs shaft be threaded over a length on either end,

sufficient to accommodate washers, spindle plates and nuts for fixing flanges

at the required spacing.

3.11.10 Normally, the nuts on the studs shall stand protruded of the flanges. All the

nails used on the inner surface of the flanges and the drum barrel shall be

counter sunk. The ends of barrel shall generally be flushed with the top of the

nuts.

3.11.11 The inner cheek of the flanges and drum barrel surface shall be painted with a

bitumen based paint.

3.11.12 Before reeling, cardboard or double corrugated or thick bituminous

waterproof bamboo paper shall be secured to the drum barrel and inside of

flanges of the drum by means of a suitable commercial adhesive material.

After reeling the earth wire, the exposed surface of the outer layer of earth

wire shall be wrapped with water proof thick bituminous bamboo paper to



8

preserve the earth wire from dirt, grit and damage during transport and

handling.

Medium grade craft/crepe/polythene paper shall be used in between the

layers.

3.11.13 A minimum space of 50 mm for earth wire shall be provided between the

inner surface of the external protective lagging and outer layer of the earth

wire.

3.11.14 Each batten shall be securely nailed across grains as far as possible to the

flange, edges with at least 2 nails per end. The length of the nails shall not be

less than twice the thickness of the battens. The nails shall not protrude above

the general surface and shall not have exposed sharp edges or allow the

battens to be released due to corrosion.

3.11.15 The nuts on the barrel studs shall be tack welded on the one side in order to

fully secure them. On the second end, a spring washer shall be used.

3.11.16 Outside the protective lagging there shall be minimum of two binder

consisting of hoop iron/galvanised steel wire. Each protective lagging shall

have two recesses to accommodate the binders.

3.11.17 The earth wire ends shall be properly sealed and secured on the side of one of

the flanges to avoid loosening of the earth wire layers during transit and

handling.

3.12 Marking

Each drum shall have the following information stenciled on it in indelible ink

along with other essential data

(a) Contract/Award letter number.

(b) Name and address of consignee.

(c) Manufacturer’s name and address.

(d) Drum number

(e) Size of earth wire

(f) Length of earth wire in meters

(g) Gross weight of drum with earth wire & lagging

(h) Weight of empty drum with lagging

(i) Arrow marking for unwinding

(j) Position of the earth wire ends



9

(k) Number of turns in the outer most layer

(l) Distance between outer most layer of Earth wire and the inner surface

of lagging

(n) Barrel diameter at three locations and an arrow marking at the location

of measurement

3.13 Verification of Earth wire Length

The Owner reserves the right to verify the length of earth wire after unreeling

atlest ten (10) percent of the drums in a lot offered for inspection.

3.14 Standards

The earth wire shall conform to the following Indian/ International Standards,

which shall mean latest revisions, amendments/changes adopted and

published, unless otherwise in the Specification.

In the event of the supply of earth wire conforming to standards other than

specified, the Contractor shall confirm in his bid that these standards are

equivalent to those specified. In case of award salient features of comparison

between the standards proposed by the Contractor and those specified in

this documents will be provided by the Contractor to establish their

equivalence.

Sl.

No.

Indian

Standard

Title International

Standard

1. IS: 209-1992 Specification for zinc BS:3436-1986

2. IS: 398-1990 Specification for Aluminium Conductors

for Overhead Transmission Purposes

IEC:1089-1991

BS:215-1970

3. IS:398-1998

Part-II

Aluminum Conductor Galvanised Steel

Reinforced

BS;215-1970

IEC:1089-1991

4. IS :398-1996

Part-IV

Aluminum Alloy stranded conductor

BS-3242-1970

ASTM-8399 M86

IEC:1089-1991

5. IS:398-1992

Part-V

Aluminum Conductor Galvanised Steel-


KV) and above

IEC:1089-1991

BS:215-1970

6. IS : 1778-

1997

Reels and Drums for Bare Conductors BS:1559-1949

7. IS : 1521-

1991

Method of Tensile Testing of Steel Wire ISO 6892-1984

8. IS : 2629-

1990

Recommended Practice for Hot Dip




10

9. IS : 2633-

1992

Method of Testing Uniformity of Coating


10. IS : 4826-

1992

Galvanised Coating on Round Steel

Wires

IEC : 888-1987

BS:443-1969

11. IS : 6745-

1991

Methods of Determination of Weight of


Steel Articles

BS:433-1969

ISO 1460 - 1973

12. IS : 8263-

1991

Method of Radio Interference Tests on


IEC:437-1973

NEMA:107-1964

CISPR

13. IS : 9997-

1991

Aluminium Alloy Redraw Rods IEC 104 - 1987

14. Zinc Coated steel wires for stranded

Conductors

IEC : 888-1987

15. Hard drawn Aluminium wire for

overhead line conductors

IEC : 889-1987



11



Name and Address




N - 19-ND

UK




1 Rue de verembe,

Geneva

SWITZERLAND


Manak Bhavan,


New Delhi - 110001.

INDIA

ISO International Organisation for

Standardization.



Aurehoegvej-12

DK-2900, Heeleprup,

DENMARK.



New York, NY 10017

U.S.A.



12

ANEXURE-A

1.0 Tests on Earth wire

1.1 UTS Test

Circles perpendicular to the axis of the earth wire shall be marked at two

places on a sample of earth wire of minimum 5 m length suitably compressed

with dead end clamps at either end. The load shall be increased at a steady

rate up to 50% of UTS and held for one minute. The circles drawn shall not be

distorted due to relative movement of strands. Thereafter the load shall be

increased at steady rate to 100% of UTS and held for one minute. The earth

wire sample shall not fail during this period. The applied load shall then be

increased until the failing load is reached and the value recorded.

1.2 D.C. Resistance Test

On a earth wire sample of minimum 5m length two contact clamps shall be

fixed with a predetermined bolt torque. The resistance shall be measured by a

Kelvin double bridge by placing the clamps initially at zero meter and

subsequently one meter apart. The test shall be repeated at least five times

and the average value recorded. The value obtained shall be corrected to the

value at 200C. The resistance corrected at 200C shall conform to the


1.3 Chemical Analysis of Zinc

Samples taken from the zinc ingots shall be chemically/ spectrographically

analyzed. The same shall be in conformity to the requirements stated in the

Specification.

1.4 Chemical Analysis of Steel

Samples taken from the steel ingots/coils/strands shall be

chemically/spectrographically analyzed. The same shall be in conformity to

the requirements stated in this Specification.

1.5 Visual and Dimensional Check on Drums and its barrel strength test.

The drums shall be visually and dimensionally checked to ensure that they

conform to the requirements of this Specification. The details regarding barrel

strength test will be discussed and mutually agreed to by Contractor and

Owner in the quality assurance programme.



13

1.6 Visual Check for Joints, Scratches etc. and Length of Earth wire

Ten percent drums from each lot shall be rewound in the presence of the

Owner. The Owner shall visually check for scratches, joints etc. and see that

the earth wire generally conforms to the requirements of this Specification.

The length of earth wire wound on the drum shall be measured with the help

of counter meter during rewinding.

1.7 Dimensional Check

The individual strands shall be dimensionally checked to ensure that they

conform to the requirement of this Specification.

1.8 Lay Length Check

The lay length shall be checked to ensure that they conform to the


1.9 Galvanizing Test

The test procedure shall be as specified in IS 4826-1979. The material shall

conform to the requirements of this Specification. The adherence of zinc shall

be checked by wrapping around a mandrel four times the diameter of steel

wire.

1.10 Torsion Test

The minimum number of twists which a single steel strand shall withstand

during torsion test shall be eighteen for a length equal to 100 times the

standard diameter of the strand. In case test sample length is less or more

than 100 times the stranded diameter of the strand the minimum number of

twists will be proportioned to the length and if number comes in the fraction

then it will be rounded off to next higher whole number.



14

Annexure-B

A) Standardized Technical Particulars of 7/3.35 mm Galvanised Steel Earth wire

Sl.

no.

Description Unit Standard Values

1.0 Raw Materials

1.1 Steel wires / rods

a) Carbon % Not more than 0.55

b) Manganese % 0.40 to 0.90

c) Phosphorous % Not more than 0.04

d) Sulphur % Not more than 0.04

e) Silicon % 0.15 to 0.35

1.2 Zinc

a) Minimum purity of Zinc % 99.95

2.0 Steel strands

2.1 Diameter

a) Nominal mm 3.35

b) Maximum mm 3.40

c) Minimum mm 3.30

2.2. Minimum breaking load of strand

a) After stranding KN 8.98

2.3 Galvanizing

a) Minimum weight of zinc coating per

sq.m. after stranding

Gms. 275

b) Minimum number of dips that the

galvanized strand can withstand in

the standard preece test

Nos. 3 dips of 1 minute

and one dip of ½

minute

c) Minimum number of twists in a

gauge length equal to 100 times

diameter of wire which the strand can

withstand in the torsion test, after

stranding

Nos. 18

3.0 Stranded Earth wire

3.1 UTS of Earth wire KN 61.1 (min.)

3.2 Lay length of outer steel layer



15

Sl.

no.

Description Unit Standard Values

a) Standard mm 181

b) Maximum mm 198

c) Minimum mm 165

3.3 Maximum DC resistance of earth

wire at 200 C

Ohm/

km

2.5

3.4 Standard length of earth wire M 2000

3.5 Tolerance on standard length % ±5

3.6 Direction of lay for outside layer Right hand

3.7 Linear mass

a) Standard Kg/km 482

b) Maximum Kg/km 496

c) Minimum Kg/km 468

Technical Specifications for Optical Ground Wire (OPGW) Cable

Section-IX-Index Page 1 of 1

Contents

Chapter– 01 : Specification for OPGW cabling & associated hardware & fittings

Chapter– 02 : Inspection & Testing Requirement

Chapter – 03 : Installation for OPGW Cabling

Appendix :

Appendix – A : Data Requirement Sheets (DRS)

Appendix A Page 1 of 2

APPENDIX – A

General Requirements

Appendix A Page 2 of 2

Table A-1

Typical Transmission line details

A1 Minimum clearance between conductor and ground (in meters)

B1 Minimum clearance between two phase conductors (in meters) – vertical in case of D/C towers and horizontal in case of S/C towers.

C1 Minimum clearance between conductor and earth wire (in meters)

Line

Voltage

S/C or

D/C

Nominal Span

(E/W &

Conductors in

mtrs.)

Wind Zone

as per

IS 802

Design Tension at

Every Day Temp (32º

C) and full wind

condition – Earthwire)

in kg for Wind Zone

Wind Pressure

(kg/Sq-m)

considering gust

factor

Max Sag –

Ground Wire

at 53ºC

(in mtrs)

UTS –

Earthwire

(in Kg)

Weight –

Earth wire

(in Kg/km)

Minimum Clearance in mtrs.

A1 B1 C1

220 kV D/C 350 IV As per 7/3.35 mm

earthwire 200

As per 7/3.35

mm earthwire 5988 482 7.015 4.5 8.5

Technical Specifications for

Optical Ground Wire (OPGW) Cable

Section-IX Appendix-A- DRS Page 1 of 4

Appendix-B

Data Requirement Sheets




Appendix-B Data Requirement Sheets The following sets of Data Requirement Sheets are required to be filled up by the bidders to aid in the evaluation process. The response shall be brief and to the point and shall be supported by the printed product description and other literature. The DRS duly filled and the relevant drawings shall also be submitted during the detailed engineering along with the relevant technical brochures.




DRS Form 1

DATA REQUIREMENTS SHEETS for OVERHEAD FIBRE OPTIC CABLE

OPTICAL GROUND WIRE (OPGW) – 24 Fibre:

(if applicable) Manufacturer: _______________________________ Part #: _______________________________ Configuration: _______________________________

CABLE CONSTRUCTION

Seq

Parameter:

As per Technical

Specification

As per Bidder Offering

1.

No. of Fibres Dual Window Single-Mode:

24

2.

Buffer Type:

Loose Tube

3.

Buffer Tube material

Non-metallic

4.

No. of Buffer Tubes:

Minimum Two (2)

5.

No. of Fibers per bufferTube:

Maximum Twelve(12)

6. Expected Cable Life: 25 Year




----------------------------------------------End of the Appendix----------------------------------------

DRS Form 2

DATA REQUIREMENTS SHEETS for OPTICAL FIBRE DUAL-WINDOW SINGLE MODE (DW-SM)

OPTICAL PARAMETERS

Seq

Parameter: As per Technical

Specification As per Bidder

offering

1. Fiber manufacturer(s) / Type:

2.

Attenuation Coefficient@ 1310 nm: @ 1550 nm:

≤ 0.35 dB/km ≤ 0.21 dB/km

3.

Point discontinuity @ 1310nm: @ 1550nm:

≤ 0.05 dB ≤ 0.05 dB

4.

Nominal Mode Field Diameter @ 1310 nm: @ 1550 nm:

8.6 to 9.5 µm (± 0.6 µm )

5.

Chromatic Dispersion Coefficient @ 1310 (1288-1339) nm: @ 1310 (1271-1360) nm: @ 1550 nm:

3.5 ps/(nmxkm) 5.3 ps/(nmxkm) 18 ps/(nmxkm)

6.

Zero dispersion wavelength: 1300 to 1324 nm

7.

Cutoff wavelength: ≤ 1260 nm

Physical and Mechanical Properties

8. Bend Performance: (37.5 mm radius, 100 turns) @1310 nm (30 mm radius, 100 turn) @1550 nm (16mm radius, 1 turn) @ 1550nm

≤ 0.05 dB

≤ 0.05 dB

≤ 0.50 dB

9. Cladding Diameter (nominal ± deviation):

125.0 µm ± 1 µm

10. Polarisation mode dispersion coefficient

≤ 0.2 ps/km1/2

11. Proof test level ≥ 0.69 Gpa



Section-IX- Chapter-01 Page 1 of 17

Chapter-01

Specification for OPGW cabling & associated hardware & fittings

Table of Content

1.0 FIBRE OPTIC CABLING .......................................................................................................... 3

1.1 REQUIRED OPTICAL FIBRE CHARACTERISTICS .......................................................... 3

1.1.1 PHYSICAL CHARACTERISTIC ............................................................................................. 3

1.1.2 ATTENUATION ........................................................................................................................... 3

1.2 FIBRE OPTIC CABLE CONSTRUCTION ............................................................................... 4

1.2.1 OPTICAL FIBRE CABLE LINK LENGTHS .......................................................................... 5

1.2.2 OPTICAL FIBRE IDENTIFICATION ...................................................................................... 5

1.2.3 BUFFER TUBE ............................................................................................................................ 5

1.2.4 OPTICAL FIBRE STRAIN & SAG-TENSION CHART ........................................................ 5

1.2.5 CABLE MATERIALS ................................................................................................................ 6

1.2.5.1 FILLING MATERIALS ............................................................................................................. 6

1.2.5.2 METALLIC MEMBERS ............................................................................................................ 7

1.2.6 MARKING, PACKAGING AND SHIPPING ........................................................................... 7

1.3. OPTICAL GROUND WIRE (OPGW) ....................................................................................... 7

1.3.1 CENTRAL FIBRE OPTIC UNIT ............................................................................................... 8

1.3.2 BASIC CONSTRUCTION .......................................................................................................... 8

1.3.3 BREAKING STRENGTH ........................................................................................................... 8

1.3.4 ELECTRICAL AND MECHANICAL REQUIREMENTS ..................................................... 9

1.3.5 OPERATING CONDITIONS ..................................................................................................... 9




1.4 INSTALLATION HARDWARE ................................................................................................ 9

1.5 FIBRE OPTIC SPLICE ENCLOSURES (JOINT BOX) ........................................................ 12

1.5.1 OPTICAL FIBRE SPLICES ..................................................................................................... 12

1.6 FIBRE OPTIC APPROACH CABLES ................................................................................... 13

1.6.1 BASIC CONSTRUCTION ........................................................................................................ 13

1.6.2 JACKET CONSTRUCTION & MATERIAL ......................................................................... 13

1.6.3 OPTICAL, ELECTRICAL AND MECHANICAL REQUIREMENTS ............................... 13

1.7 FIBRE OPTIC DISTRIBUTION PANEL ............................................................................... 13

1.7.1 OPTICAL FIBRE CONNECTORS .......................................................................................... 14

1.8 SERVICE LOOPS ..................................................................................................................... 14

1.9 TEST EQUIPMENT .................................................................................................................. 14

2.0 Applicable Standards...........................................................................................................15




Section-01

Specification for OPGW cabling and associated hardware & fittings

The broad scope of this specification include the survey, planning, design, engineering, manufacturing,

supply, transportation, insurance, delivery at site, unloading, handling, storage, , installation, splicing,

termination, testing, demonstration for acceptance and commissioning and documentation for:

a) OPGW fibre optic cable including all associated hardware, accessories & fittings

b) Fibre Optic approach cable including installation material

c) Fibre Optic Distribution Panels (FODP) & Joint Box

d) Supply of spares

e) Supply of test equipments

f) All other associated work/items described in the technical specifications.

This section of the technical specification describes the functional and technical specifications of

OPGW cabling and associated hardware and fittings.

1.0 Fibre Optic Cabling

In this section of the technical specification, the functional & technical specifications of OPGW cable,

associated hardware & fittings for the requirements for G.652D Dual-window Single mode (DWSM)

telecommunications grade fibre optic cable is mentioned. Bidders shall furnish with their bids, detailed

descriptions of the fibres & cable(s) proposed.

All optical fibre cabling including fibre itself and all associated installation hardware shall have a

minimum guaranteed design life span of 25 years. Documentary evidence in support of guaranteed life

span of cable & fibre shall be submitted by the Contractor during detailed engineering.

1.1 Required Optical Fibre Characteristics

The optical fibre to be provided should have following characteristics :

1.1.1 Physical Characteristic

Dual-Window Single mode (DWSM), G.652D optical fibres shall be provided in the fibre optic cables.

DWSM optical fibres shall meet the requirements defined in Table 1-1(a).

1.1.2 Attenuation

The attenuation coefficient for wavelengths between 1525 nm and 1575 nm shall not exceed the

attenuation coefficient at 1550 nm by more than 0.05 dB/km. The attenuation coefficient between 1285

nm and 1330 nm shall not exceed the attenuation coefficient at 1310 nm by more than 0.05 dB/km.

The attenuation of the fibre shall be distributed uniformly throughout its length such that there are no

point discontinuities in excess of 0.10 dB. The fibre attenuation characteristics specified in table 1-1

(a) shall be “guaranteed” fibre attenuation of any & every fibre reel.




The overall optical fibre path attenuation shall not be more than calculated below :

Maximum attenuation @ 1550 nm : 0.21 dB/km x total km + 0.05 dB/splice x no. of splices + 0.5

dB/connector x no. of connectors.

Maximum attenuation @ 1310 nm : 0.35 dB/km x total km + 0.05 dB/splice x no. of splices + 0.5

dB/connector x no. of connectors.

1.2 Fibre Optic Cable Construction

The OPGW (Optical Ground Wire) cable is proposed to be installed on the new transmission lines

alongwith transmission line construction. The design of cable shall account for the varying operating

and environmental conditions that the cable shall experience while in service. The OPGW cable to

Table 2-1(a)

DWSM Optical Fibre Characteristics Fibre Description:

Dual-Window Single-Mode Mode Field Diameter:

8.6 to 9.5 m (± 0.6m ) Cladding Diameter:

125.0 m ± 1 m Mode field concentricity error

0.6m Cladding non-circularity

Cable Cut-off Wavelength cc

1260 nm 1550 nm loss performance

As per G.652 D

Proof Test Level

0.69 Gpa Attenuation Coefficient:

@ 1310 nm 0.35 dB/km

@ 1550 nm 0.21 dB/km Chromatic Dispersion; Maximum:

Zero Dispersion Wavelength :

Zero Dispersion Slope :

18 ps/(nm x km) @ 1550 nm

3.5 ps/(nm x km) 1288-1339nm

5.3 ps/(nm x km) 1271-1360nm

1300 to 1324 nm

0.092 ps/(nm2xkm) maximum

Polarization mode dispersion

coefficient 0.2 ps/km^½

Temperature Dependence :

Induced attenuation 0.05 dB (-60C - +85C )

Bend Performance :

@ 1310 nm (75±2 mm dia Mandrel), 100 turns;

Attenuation Rise 0.05 dB/km

@ 1550 nm (75±2 mm dia Mandrel), 100 turns;


@ 1550 nm (32±0.5 mm dia Mandrel, 1 turn;





be supplied shall be designed to meet the overall requirements of all the transmission lines. The

Tower span details shall be collected by the contractor during survey. To meet the overall

requirement of the transmission line(s), the contractor may offer more than one design without

any additional cost to Employer, in case single design is not meeting the requirement. OPGW cable

to be designed to meet transmission line sag-tension parameters and other details to be provided by

Transmission Line contractor. Any other details, as required for cable design etc. shall be collected

by the Contractor during survey.

1.2.1 Optical Fibre Cable Link Lengths

The estimated optical fibre link lengths are provided in Appendices as transmission line route length.

However, the Contractor shall supply the OPGW cable as required based on the tower schedule. The

Contractor shall verify the transmission line route length during the survey and the Contract price

shall be adjusted accordingly.

For the purpose of payment, the optical fibre link lengths are defined as transmission line route

lengths from Gantry at one terminating station to the Gantry in the other terminating station. The

actual cable lengths to be delivered shall take into account various factors such as sag, service loops,

splicing, working lengths & wastage etc. and no additional payment shall be payable in this regard.

The unit rate for FO cable quoted in the Bid price Schedules shall take into account all such factors.

1.2.2 Optical Fibre Identification

All optical fibres shall be individually coated. Individual optical fibres within a fibre unit and fibre

units shall be identifiable in accordance with EIA/TIA 598 or IEC 60304 or Bellcore GR-20 colour-

coding scheme.

Colouring utilized for colour coding optical fibres shall be integrated into the fibre coating and shall

be homogenous. The colour shall not bleed from one fibre to another and shall not fade during fibre

preparation for termination or splicing.

Each cable shall have traceability of each fibre back to the original fibre manufacturer's fibre number

and parameters of the fibre. If more than the specified number of fibres is included in any cable, the

spare fibres shall be tested by the cable manufacturer and any defective fibres shall be suitably

bundled, tagged and identified at the factory by the vendor.

1.2.3 Buffer Tube

Loose tube construction shall be implemented. The individually coated optical fibre(s) shall be

surrounded by a buffer for protection from physical damage during fabrication, installation and

operation of the cable. The fibre coating and buffer shall be strippable for splicing and

termination. Each fibre unit shall be individually identifiable utilizing colour coding. Buffer tubes

shall be filled with a water-blocking gel.

1.2.4 Optical Fibre Strain & Sag-Tension chart




The OPGW cable shall be designed and installed such that the optical fibres experience no strain

under all loading conditions of transmission lines. Zero fibre strain condition shall apply even after a

25 year cable creep.

For the purpose of this specification, the following definitions shall apply:

Maximum Working Tension (MWT) is defined as the maximum cable tension at which there is

no fibre strain.

The no fibre strain condition is defined as fibre strain of less than or equal to 0.05%, as

determined by direct measurements through IEC/ ETSI (FOTP) specified optical reflectometry

The Cable strain margin is defined as the maximum cable strain at which there is no fibre

strain.

The cable Maximum Allowable Tension (MAT) is defined as the maximum tension

experienced by the Cable under the worst case loading condition.

The cable max strain is defined as the maximum strain experienced by the Cable under the

worst case loading condition.

The cable Every Day Tension (EDT) is defined as the maximum cable tension on any span

under normal conditions.

The Ultimate /Rated Tensile Strength (UTS/ RTS/ breaking strength) is defined as the

maximum tensile load applied and held constant for one minute at which the specimen shall

not break.

While preparing the Sag-tension charts for the OPGW cable the following conditions shall be met:

The Max Allowable Tension (MAT) / max strain shall be less than or equal to the MWT/

Strain margin of the cable.

The sag shall not exceed the earth wire sag in all conditions.

The Max Allowable Tension shall also be less than or equal to 0.4 times the UTS.

The 25 year creep at 25% of UTS (creep test as per IEEE 1138) shall be such that the 25 year

creep plus the cable strain at Max Allowable Tension (MAT) is less than or equal to the

cable strain margin.

The everyday tension (EDT) shall not exceed 20% of the UTS for the OPGW cable.

The Sag-tension chart of OPGW cable indicating the maximum tension, cable strain and sag shall

be calculated and submitted along with the bid under various conditions as per tower design of the

transmission line.

The size of OPGW shall be selected such that max. tension and sag at specified temperature and

wind condition remains within the limits of transmission line tower design.

1.2.5 Cable Materials

The materials used for optical fibre cable construction, shall meet the following requirements:

1.2.5.1 Filling Materials

The interstices of the fibre optic unit and cable shall be filled with a suitable compound to prohibit

any moisture ingress or any water longitudinal migration within the fibre optic unit or along the fibre




optic cable. The water tightness of the cable shall meet or exceed the test performance criteria as per

IEC 60794-1-F-5.

The filling compound used shall be a non-toxic homogenous waterproofing compound that is free of

dirt and foreign matter, non-hygroscopic, electrically nonconductive and non-nutritive to fungus. The

compound shall also be fully compatible with all cable components it may come in contact with and

shall inhibit the generation of hydrogen within the cable.

The waterproofing filling materials shall not affect fibre coating, colour coding, or encapsulant

commonly used in splice enclosures, shall be dermatologically safe, non-staining and easily

removable with a non-toxic cleaning solvent.

1.2.5.2 Metallic Members

When the fibre optic cable design incorporates metallic elements in its construction, all metallic

elements shall be electrically continuous.

1.2.6 Marking, Packaging and Shipping

This section describes the requirements for marking, packaging and shipping the overhead fibre optic

cable.

(a) Drum Markings: Each side of every reel of cable shall be permanently marked in white lettering

with the vendors' address, the Purchaser’s destination address, cable part number and

specification as to the type of cable, length, number of fibres, a unique drum number including

the name of the transmission line & segment no., factory inspection stamp and date.

(b) Cable Drums: All optical fibre cabling shall be supplied on strong drums provided with lagging

of adequate strength, constructed to protect the cabling against all damage and displacement

during transit, storage and subsequent handling during installation. Both ends of the cable shall

be sealed as to prevent the escape of filling compounds and dust & moisture ingress during

shipment and handling. Spare cable caps shall be provided with each drum as required.

The spare cable shall be supplied on sturdy, corrosion resistant, steel drums suitable for long

periods of storage and re-transport & handling.

There shall be no factory splices allowed within a continuous length of cable. Only one continuous

cable length shall be provided on each drum. The lengths of cable to be supplied on each drum shall

be determined by a "schedule" prepared by the Contractor and approved by the owner.

1.3. Optical Ground Wire (OPGW)

OPGW cable construction shall comply with IEEE-1138, 2009. The cable provided shall meet both

the construction and performance requirements such that the ground wire function, the optical fibre

integrity and optical transmission characteristics are suitable for the intended purpose. The cable

shall consist of optical fibre units as defined in this specification. There shall be no factory splices

within the cable structure of a continuous cable length.




The composite fibre optic overhead ground wire shall be made up of multiple buffer tubes embedded

in a water tight aluminium/aluminium alloy protective central fibre optic unit surrounded by

concentric-lay stranded metallic wires in single or multiple layers. Each buffer tube shall have

maximum 12 no. of fibres. All fibres in single buffer tube or directly in central fibre optic unit is not

acceptable. The dual purpose of the composite cable is to provide the electrical and physical

characteristics of conventional overhead ground wire while providing the optical transmission

properties of optical fibre.

1.3.1 Central Fibre Optic Unit

The central fibre optic unit shall be designed to house and protect multiple buffered optical fibre

units from damage due to forces such as crushing, bending, twisting, tensile stress and moisture. The

central fibre optic unit and the outer stranded metallic conductors shall serve together as an integral

unit to protect the optical fibres from degradation due to vibration and galloping, wind and ice

loadings, wide temperature variations, lightning and fault current, as well as environmental effects

which may produce hydrogen.

The OPGW design of dissimilar materials for stranded wires and tubes are not allowed. Central fibre

optic unit may be of aluminium / aluminium alloy tube. There shall be no exposed areas of tubing

that can make electrical contact either directly or indirectly through moisture, contamination,

protrusions, etc with the surrounding stranded wires. The tube may be fabricated as a seamless tube,

seam welded, or a tube without a welded seam.

1.3.2 Basic Construction

The OPGW cable construction shall conform to the applicable requirements of this specification,

applicable clauses of IEC 61089 related to stranded conductors and Table 1.2(a) OPGW Mechanical

and Electrical Characteristics. In addition, the basic construction shall include bare concentric-lay-

stranded metallic wires with the outer layer having left hand lay. The wires may be of multiple layers

with a combination of various metallic wires within each layer. The direction of lay for each

successive layer shall be reversed. The finished wires shall contain no joints or splices unless

otherwise agreed to by the Employer and shall conform to all applicable clauses of IEC 61089 as

they pertain to stranded conductors.

The wires shall be so stranded that when the complete OPGW is cut, the individual wires can be

readily regrouped and then held in place by one hand.

1.3.3 Breaking Strength

The rated breaking strength of the completed OPGW shall be taken as no more than 90 percent of the

sum of the rated breaking strengths of the individual wires, calculated from their nominal diameter

and the specified minimum tensile strength.

The rated breaking strength shall not include the strength of the optical unit. The fibre optic unit shall

not be considered a load bearing tension member when determining the total rated breaking strength

of the composite conductor.




1.3.4 Electrical and Mechanical Requirements

Table 1-2(a) provides OPGW Electrical and Mechanical Requirements for the minimum

performance characteristics. Additionally, the OPGW mechanical & electrical characteristics shall be

similar to that of the earthwire being replaced such that there is no or minimal consequential increase

in stresses on towers. OPGW installation sag & tension charts shall be as per transmission line

requirement. For the OPGW cable design selection and preparation of sag tension charts, the limits

specified in this section shall also be satisfied. The Bidder shall submit sag-tension charts for the

above cases with their bids.

Table 1.2(a)

OPGW Electrical and Mechanical Requirements

(1) Everyday Tension

≤ 20% of UTS of OPGW

(2)

D.C. Resistance at 20ºC:

< 1.0 ohm/Km or Employer provided values

(3)

Short Circuit Current

≥ 6.32 kA for 1.0 second or Employer provided values

Bidder may offer separate design for each short circuit rating however OPGW design with higher

short circuit level shall be acceptable.

1.3.5 Operating conditions

Since OPGW shall be located at the top of the transmission line support structure, it will be

subjected to Aeolian vibration, Galloping and Lightning strikes. It will also carry ground fault

currents. Therefore, its electrical and mechanical properties shall be same or similar as those required

of conventional ground conductors.

1.4 Installation Hardware

The scope of supply includes all required fittings and hardware such as Tension assembly,

Suspension assembly, Vibration dampers, Reinforcing rods, Earthing clamps, Downlead clamps,

splice enclosure etc. The Bidder shall provide documentation justifying the adequacy and suitability

of the hardware supplied. The quantity of hardware & fittings to meet any eventuality during site

installation minimum@ 1% shall also be provided as part of set/km for each transmission line

without any additional cost to Employer.

The OPGW hardware fittings and accessories shall follow the general requirements regarding design,

materials, dimensions & tolerances, protection against corrosion and markings as specified in clause

4.0 of EN 61284: 1997 (IEC 61284). The shear strength of all bolts shall be at least 1.5 times the

maximum installation torque. The OPGW hardware & accessories drawing & Data Requirement

Sheets (DRS) document shall consist of three parts: (1) A technical particulars sheet (2) An assembly

drawing i.e. level 1 drawing and (3) Component level drawings i.e. level 2 & lower drawings. All

component reference numbers, dimensions and tolerances, bolt tightening torques & shear strength

and ratings such as UTS, slip strength etc shall be marked on the drawings.




The fittings and accessories described herein are indicative of installation hardware typically used for

OPGW installations and shall not necessarily be limited to the following:

(a) Suspension Assemblies: Preformed armour grip suspension clamps and aluminium alloy

armour rods/ reinforcing rods shall be used. The suspension clamps shall be designed to carry

a vertical load of not less than 25 KN. The suspension clamps slippage shall occur between

12kN and 17 kN as measured.

The Contractor shall supply all the components of the suspension assembly including

shackles, bolts, nuts, washers, split pins, etc. The total drop of the suspension assembly shall

not exceed 150 mm (measured from the centre point of attachment to the centre point of the

OPGW). The design of the assembly shall be such that the direction of run of the OPGW

shall be the same as that of the conductor.

(b) Dead End Clamp Assemblies: All dead end clamp assemblies shall preferably be of

performed armoured grip type and shall include all necessary hardware for attaching the

assembly to the tower strain plates. Dead end clamps shall allow the OPGW to pass through

continuously without cable cutting. The slip strength shall be rated not less than 95% of the

rated tensile strength of the OPGW.

(c) Clamp Assembly Earthing Wire: Earthing wire consisting of a 1500 mm length of

aluminium or aluminium alloy conductor equivalent in size to the OPGW shall be used to

earth suspension and dead end clamp assemblies to the tower structure. The earthing wire

shall be permanently fitted with lugs at each end. The lugs shall be attached to the clamp

assembly at one end and the tower structure at the other.

(d) Structure Attachment Clamp Assemblies: Clamp assemblies used to attach the OPGW to the

structures, shall have two parallel grooves for the OPGW, one on either side of the

connecting bolt. The clamps shall be such that clamping characteristics do not alter adversely

when only one OPGW is installed. The tower attachment plates shall locate the OPGW on

the inside of the tower and shall be attached directly to the tower legs/cross-members without

drilling or any other structural modifications.

(e) Vibration Dampers: Vibration dampers type 4R Stockbridge or equivalent, having four (4)

different frequencies spread within the Aeolian frequency bandwidth corresponding to wind

speed of 1m/s to 7 m/s, shall be used for suspension and tension points in each span. The

Contractor shall determine the exact numbers and placement(s) of vibration dampers

through a detailed vibration analysis as specified in technical specifications.

One damper minimum on each side per OPGW cable for suspension points and two

dampers minimum on each side per OPGW cable for tension points shall be used for

nominal design span of 350 meters. For all other ruling spans, the number of vibration

damper shall be based on vibration analysis.

The clamp of the vibration damper shall be made of high strength aluminum alloy of type

LM-6. It shall be capable of supporting the damper and prevent damage or chaffing of the

conductor during erection or continued operation. The clamp shall have smooth and

permanent grip to keep the damper in position on the OPGW cable without damaging the




strands or causing premature fatigue failure of the OPGW cable under the clamp. The clamp

groove shall be in uniform contact with the OPGW cable over the entire clamping surface

except for the rounded edges. The groove of the clamp body and clamp cap shall be smooth,

free from projections, grit or other materials which could cause damage to the OPGW cable

when the clamp is installed. Clamping bolts shall be provided with self locking nuts and

designed to prevent corrosion of threads or loosening in service.

The messenger cable shall be made of high strength galvanised steel/stain less steel. It shall

be of preformed and post formed quality in order to prevent subsequent droop of weight and

to maintain consistent flexural stiffness of the cable in service. The messenger cable other

than stainless steel shall be hot dip galvanised in accordance with the recommendations of

IS: 4826 for heavily coated wires.

The damper mass shall be made of hot dip galvanised mild steel/cast iron or a permanent

mould cast zinc alloy. All castings shall be free from defects such as cracks, shrinkage,

inclusions and blow holes etc. The surface of the damper masses shall be smooth.

The damper clamp shall be casted over the messenger cable and offer sufficient and

permanent grip on it. The messenger cable shall not slip out of the grip at a load less than

the mass pull-off value of the damper. The damper masses made of material other-than zinc

alloy shall be fixed to the messenger cable in a suitable manner in order to avoid excessive

stress concentration on the messenger cables which shall cause premature fatigue failure of

the same. The messenger cable ends shall be suitably and effectively sealed to prevent

corrosion. The damper mass made of zinc alloy shall be casted over the messenger cable and

have sufficient and permanent grip on the messenger cable under all service conditions.

The contractor must indicate the clamp bolt tightening torque to ensure that the slip strength

of the clamp is maintained between 2.5 kN and 5 kN. The clamp when installed on the

OPGW cable shall not cause excessive stress concentration on the OPGW cable leading to

permanent deformation of the OPGW strands and premature fatigue failure in operation.

The vibration analysis of the system, with and without damper and dynamic characteristics

of the damper as detailed in Technical Specification, shall have to be submitted. The

technical particulars for vibration analysis and damping design of the system are as follows:

Sl. No. Description Technical Particulars

1 Span Length in meters

(i) Ruling design span:

(ii) Maximum span:

(iii) Minimum Span:

350 meters

1100 meters

100 meters

2 Configuration: As per Specifications




3 Tensile load in each: As per sag tension calculations

4 Armour rods used: Standard preformed armour

rods/AGS

5 Maximum permissible dynamic strain: +/- 150 micro strains

The damper placement chart for spans ranging from 100m to 1100m shall be submitted by

the Contractor. Placement charts should be duly supported with relevant technical

documents and sample calculations.

The damper placement charts shall include the following

(1) Location of the dampers for various combinations of spans and line tensions clearly

indicating the number of dampers to be installed per OPGW cable per span.

(2) Placement distances clearly identifying the extremities between which the distances are

to be measured.

(3) Placement recommendation depending upon type of suspension clamps (viz Free center

type/Armour grip type etc.)

(4) The influence of mid span compression joints, repair sleeves and armour rods (standard

and AGS) in the placement of dampers

1.5 Fibre Optic Splice Enclosures (Joint Box)

All splices shall be encased in Fibre Optic Splice Enclosures. Suitable splice enclosures shall be

provided to encase the optical cable splices in protective, moisture and dust free environment. Splice

enclosures shall comply with ingress protection class IP 66 or better. The splice enclosures shall be

designed for the storage and protection of required number of optical fibre splices and equipped with

sufficient number of splice trays for splicing all fibres in the cable. No more than 12 fibres shall be

terminated in a single splice tray. They shall be filled with suitable encapsulate that is easily

removable should re-entry be required into the enclosures.

Splice enclosures shall be suitable for outdoor use with each of the cable types provided under this

contract. Splice enclosures shall be appropriate for mounting on transmission line towers above anti-

climb guard levels at about 10 metres from top of the tower and shall accommodate pass-through

splicing. The actual mounting height and location shall be finalised after Survey. Contractor shall be

responsible for splicing of fibres and installation of splice enclosures.

1.5.1 Optical Fibre Splices

Splicing of the optical fibre cabling shall be minimized through careful Contractor planning. There

shall be no mid-span splices allowed. All required splices shall be planned to occur on tower

structures. All optical fibre splicing shall comply with the following:

(a) All fibre splices shall be accomplished through fusion splicing.




(b) Each fibre splice shall be fitted with a splice protection sheath fitted over the final splice.

(c) All splices and bare fibre shall be neatly installed in covered splice trays.

(d) For each link, bi-directional attenuation of single mode fusion splices, shall not average more

than 0.05 dB and no single splice loss shall exceed 0.1 dB when measured at 1550 nm.

(e) For splicing, fibre optic cable service loops of adequate length shall be provided so that all

splices occurring at tower structures can be performed at ground level.

1.6 Fibre Optic Approach Cables

For purposes of this specification, a fibre optic approach cable is defined as the Armoured

underground fibre optic cable required to connect Overhead Fibre Optic Cable (OPGW) between the

final in line splice enclosure on the gantry / tower forming the termination of the fibre cable on the

power line and the Fibre Optic Distribution Panel (FODP) installed within the building. The

estimated fibre optic approach cabling length requirements are indicated in the appendices. However,

the Contractor shall supply & install the optical fibre approach cable as required based on detailed

site survey to be carried out by the Contractor during the project execution and the Contract price

shall be adjusted accordingly.

1.6.1 Basic Construction

The cable shall be suitable for direct burial, laying in trenches & PVC/Hume ducts, laying under

false flooring and on indoor or outdoor cable raceways.

1.6.2 Jacket Construction & Material

The Approach Cable shall be a UV resistant, rodent proof, armoured cable with metallic type of

armouring. The outer cable jacket for approach cable shall consist of carbon black polyethylene resin

to prevent damage from exposure to ultra-violet light, weathering and high levels of pollution. The

jacket shall conform to ASTM D1248 for density.

1.6.3 Optical, Electrical and Mechanical Requirements

Approach cable shall contain fibres with identical optical/ physical characteristics as those in the

OPGW cables. The cable core shall comprise of tensile strength member(s), fibre support/bedding

structure, core wrap/bedding, and an overall impervious jacket.

1.7 Fibre Optic Distribution Panel

Fibre Optic Distribution Panels is required for each location for termination of fibres in a manner

consistent with the following:

(a) FODPs shall be suitable for use with each of the cable types provided as part of this contract.

FODPs shall accommodate pass-through splicing and fibre terminations.

(b) FODPs for indoor use shall be supplied in suitable cabinets/racks with locking arrangement




(c) All FODPs shall be of corrosion resistant, robust construction and shall allow both top or bottom

entry for access to the splice trays. Ground lugs shall be provided on all FODPs and the

Contractor shall ensure that all FODPs are properly grounded. The FODP shall meet or exceed

ingress protection class IP55 specifications.

1.7.1 Optical Fibre Connectors

Optical fibres shall be connectorised with FC-PC type connectors preferably. Alternatively connector

with matching patch cord shall also be acceptable. Fibre optic couplings supplied with FODPs shall

be appropriate for the fibre connectors to be supported. There shall be no adapters.

1.8 Service Loops

For purposes of this specification, cable and fibre service loops are defined as slack (extra) cable and

fibre provided for facilitating the installation, maintenance and repair of the optical fibre cable plant.

(a) Outdoor Cable Service Loops: In-line splice enclosures installed outdoors and mounted on the

utility towers shall be installed with sufficient fibre optic cable service loops such that the

recommended minimum bend radius is maintained while allowing for installation or

maintenance of the cable to be performed in a controlled environment at ground level.

(b) Indoor Cable Service Loops: FODPs shall provide at least three (3) metres of cable service

loop. Service loops shall be neatly secured and stored, coiled such that the minimum

recommended bend radius' are maintained.

(c) Fibre Units Service Loops: For all fibre optic cable splicing, the cable shall be stripped back a

sufficient length such that the fan-out of fibre units shall provide for at least one (1) metre of

fibre unit service loop between the stripped cable and the bare fibre fan-out.

(d) Pigtail Service Loops : Connectorised pigtails spliced to bare fibres shall provide at least 1

metre of service loop installed in the FODP fibre organizer and at least one (1) metre of service

loop to the couplings neatly stored behind the FODP coupling panels.

(e) Fibre Service Loops : At least 0.5 metre of bare fibre service loop shall be provided on each

side of all fibre splices. The bare fibre service loops shall be neatly and safely installed inside

covered splice trays.

1.9 Test Equipment

The table 1.3 below provides mandatory test equipment requirements, to be provided as applicable as

per BoQ. The parameters / features of the mandatory equipments are enumerated as follows :

Table 1.3

S. No. Test equipment Parameter

A. Test Equipments for OPGW cable




1

OTDR (Optical Time Domain

Reflectometer) for 1310/1550 nm with

laser source.

Equivalent to Anritsu MW9076B1 or better.

2 Optical Attenuators (variable

1310/1550nm).

Equivalent to JDSU OLA55 or better.

3 Optical Power meter (1310/1550nm)

Equivalent to JDSU OLP55 or better

4 Optical Talk set

Equivalent to JDSU OTS55 or better.

5 Optical Fibre Fusion Splicer incl. Fibre

cleaver

Equivalent to Sumitomo T-39-SE or better.

6 Calibrated Fibre

7 Connectorization kit FIS – FI-0053-FC-INST or equivalent

8 Splice kit FIS – FI-0053-FF or equivalent

9

Optical test accessory kit including all

necessary connectors, adaptors, cables,

terminations and other items required for

testing

FIS – FI-0053-TS-ST or equivalent

In case the offered make/model of test equipment has multiple options for the parameters, the option of

higher range shall be acceptable. The supplied test equipment shall be suitable for use in the high

EMI/EMC environment. The Contractor shall submit performance certificate for offered test

equipment from at least one customer. The Contractor shall offer only reputed make test equipment

such as Acterna (JDSU)/Anritsu/Sumitomo/Agilent/EXFO etc.

2.0 Applicable Standards

The following standards and codes shall be generally applicable to the equipment and works supplied

for OPGW and associated Items

(1) American Society for Testing and Materials ASTM

ASTM-B415 Standard Specification for Hard-Drawn Aluminium-Clad Steel

Wire

(2) Bell Communication Research

GR-20 Generic requirements for optical fibre and optical fibre cable

(3) ITU-T/CCITT Recommendations

G.650 Definitions and test methods for the relevant parameters of single-

mode fibres

G.652 Characteristics of a single-mode optical fibre cable




(4) IEEE

IEEE-1138 IEEE Standard Construction of Composite Fibre Optic Ground

Wire (OPGW) for Use on Electric Utility power Lines

(5) Telecommunication Industry Association EIA/TIA

EIA/TIA-455-3 Procedure to Measure Temperature Cycling Effects on Optical

Fibres, Optical Cable, and Other Passive Fiber Optic Components

EIA/TIA-455-16 Salt Spray (Corrosion) Test for Fibre Optic Components

EIA/TIA-455-20 Measurement of Change in Optical Transmittance

EIA/TIA-455-25 Repeated Impact Testing of Fibre Optic Cables and Cable

Assemblies

EIA/TIA-455-32 Fibre Optic Circuit Discontinuities

EIA/TIA-455-33 Fibre Optic Cable Tensile Loading and Bending Test

EIA/TIA-455-41 Compressive Loading Resistance of Fibre Optic Cables

EIA/TIA-455-59 Measurement of Fibre Point Defects Using an OTDR

EIA/TIA-455-62 Measurement of Optical Fibre Macrobend Attenuation

EIA/TIA-455-78 Spectral Attenuation Cutback Measurement for Single- Mode

Optical Fibres

EIA/TIA-455-80 Measurement of Cut-Off Wavelength of Single-Mode Fibre by

Transmitted Power

EIA/TIA-455-81 Compound Flow (Drip) Test for Filled Fibre Optic Cable

EIA/TIA-455-82 Fluid Penetration Test for Fluid-Blocked Fibre optic Cable

EIA/TIA-455-91 Fibre Optic Cable Twist-Bend Test

EIA/TIA-455-164 Single-Mode Fibre, Measurement of Mode Field Diameter by Far-

Field Scanning

EIA/TIA-455-167 Mode Field Diameter Measurement, Variable Aperture Method in

the Far-Field

EIA/TIA-455-168 Chromatic Dispersion Measurement of Multimode Graded Index

and Single-Mode Optical Fibres by Spectral Group Delay

Measurement in the Time Domain

EIA/TIA-455-169 Chromatic Dispersion Measurement of Single-Mode Optical Fibres

by the Phase-Shift Method

EIA/TIA-455-170 Cable Cut-off Wavelength of Single-Mode Fibre by Transmitted

Power

EIA/TIA-455-174 Mode Field Diameter Measurement

EIA/TIA-455-175 Chromatic Dispersion Measurement of Single-Mode Optical Fibres

by the Differential Phase-Shift Method

EIA/TIA-455-176 Method of Measuring Optical Fibre Cross-Sectional Geometry by

Automated Grey-Scale Analysis

EIA/TIA-598 Optical Fibre Cable Colour Coding

(6) International Electrotechnical Commission IEC standards

IEC-60793-1 series Optical fibres – Generic & product specifications, measurement

methods & test procedures specification

IEC-60794-1-1 Optical fibre cables – Generic specification




IEC-60794-1-2 Optical fibre cables – Basic optical cable test procedure

IEC-60794-3 Optical fibre cables – Duct, buried and aerial cables – sectional

specification

IEC-60794-4 Optical fibre cables – Overhead cables

IEC-61089 Round wire concentric lay overhead electrical stranded conductors

IEC-61232 Aluminium-clad steel wires for electrical purposes

IEC-61284 Overhead lines-Requirements and tests for fittings

IEC-61395 Overhead electrical conductors – Creep test procedures for

stranded conductors

Specifications and codes shall be the latest version, inclusive of revisions, which are in force at the

date of the contract award. Where new specifications, codes, and revisions are issued during the period

of the contract, the Contractor shall attempt to comply with such, provided that no additional expenses

are charged to the Employer without Employer’s written consent.

In the event the Contractor offers to supply material and/or equipment in compliance to any standard

other than Standards listed herein, the Contractor shall include with their proposal, full salient

characteristics of the new standard for comparison.

In case values indicated for certain parameters in the specifications are more stringent than those

specified by the standards, the specification shall override the standards.

I.10 References

(1) CIGRE Guide for Planning of Power Utility Digital Communications Networks

(2) CIGRE Optical Fibre Planning Guide for Power Utilities

(3) CIGRE New Opportunities for Optical Fibre Technology in Electricity Utilities

(4) CIGRE guide to fittings for Optical Cables on Transmission Lines

…………………….……..…End of this Section……………………………...




Chapter - 02

Inspection & Testing Requirement

Table of Content

2.1 Testing Requirements ................................................................................................ 2

2.1.1 Type Testing ........................................................................................................ 3

2.1.2 Type Test Samples .............................................................................................. 4

2.1.3 List of Type Tests ................................................................................................ 4

2.1.3.1 Type Tests for Optical Fibres ........................................................................... 4

2.1.3.2 Type Tests for OPGW Cables .......................................................................... 5

2.1.3.3 Type Test on OPGW Cable Fittings ............................................................. 10

2.1.3.4 Type Test on Vibration Damper .................................................................... 13

2.1.3.5 Type Tests for Splice Enclosures (Joint Box) ................................................ 16

2.1.3.6 Type Tests for Fibre Optic Approach Cable .................................................. 18

2.2 Factory Acceptance Tests ........................................................................................ 18

2.2.1 Sampling for FAT ............................................................................................. 19

2.2.2 Production Testing ............................................................................................ 20

2.2.3 Factory Acceptance Tests on Optical Fibre to be supplied with OPGW .......... 20

2.2.4 Factory Acceptance Test on OPGW Cable ....................................................... 20

2.2.5 Factory Acceptance Test on OPGW Fittings .................................................... 21

2.2.6 Factory Acceptance Test on Approach Cable ................................................... 22

2.2.7 Factory Acceptance Test on Splice Enclosure (Joint Box) /FODP ................... 23

2.2.8 Factory Acceptance Test on Test Equipment & other items ............................. 23

2.3 Site Acceptance Tests .............................................................................................. 23

2.3.1 Minimum Site Acceptance Testing Requirement for FO Cabling .................... 23

2.3.1.1 Phases of Site Acceptance Testing ................................................................. 24




Section - 02

Inspection & Testing Requirement

All materials furnished and all work performed under this Contract shall be inspected and

tested. Deliverables shall not be shipped until all required inspections and tests have been

completed, and all deficiencies have been corrected to comply with this Specification and

approved for shipment by the Employer.

Except where otherwise specified, the Contractor shall provide all manpower and materials

for tests, including testing facilities, logistics, power and instrumentation, and replacement of

damaged parts. The costs shall be borne by the Contractor and shall be deemed to be included

in the contract price.

The entire cost of testing for factory, production tests and other test during manufacture

specified herein shall be treated as included in the quoted unit price of materials, except for

the expenses of Inspector/Employer’s representative.

Acceptance or waiver of tests shall not relieve the Contractor from the responsibility to

furnish material in accordance with the specifications.

All tests shall be witnessed by the Employer and/or its authorized representative (hereinafter

referred to as the Employer) unless the Employer authorizes testing to proceed without

witness. The Employer representative shall sign the test form indicating approval of

successful tests.

Should any inspections or tests indicate that specific item does not meet Specification

requirements, the appropriate items shall be replaced, upgraded, or added by the Contractor

as necessary to correct the noted deficiencies at no cost to the Employer. After correction of a

deficiency, all necessary retests shall be performed to verify the effectiveness of the

corrective action.

The Employer reserves the right to require the Contractor to perform, at the Employer's

expense, any other reasonable test(s) at the Contractor's premises, on site, or elsewhere in

addition to the specified Type, Acceptance, Routine, or Manufacturing tests to assure the

Employer of specification compliance.

2.1 Testing Requirements

Following are the requirements of testing :

1. Type Testing

2. Factory Acceptance Testing

3. Site Acceptance Testing




2.1.1 Type Testing

"Type Tests" shall be defined as those tests which are to be carried out to prove the design,

process of manufacture and general conformity of the materials to this Specification. Type

Testing shall comply with the following:

(a) All cable & equipment being supplied shall conform to type tests as per

technical specification.

(b) The test reports submitted shall be of the tests conducted within last seven (7)

years for OPGW cable prior to the date of proposal/offer submitted. In case the

test reports are older than seven (7) years for OPGW cable on the date of

proposal/offer, the Contractor shall repeat these tests at no extra cost to the

Employer.

(c) The Contractor shall submit, within 30 days of Contract Award, copies of test

reports for all of the Type Tests that are specified in the specifications and that

have previously ( before Contract award) been performed. These reports may be

accepted by the Employer only if they apply to materials and equipment that are

essentially identical to those due to be delivered under the Contract and only if

test procedures and parameter values are identical to those specified in this

specifications carried out at accredited labs and witnessed by third party /

customer’s representatives.

In the event of any discrepancy in the test reports or any type tests not carried

out, same shall be carried out by Contractor without any additional cost

implication to the Employer.

In case the Type Test is required to be carried out, then following shall be

applicable:-

(d) Type Tests shall be certified or performed by reputed laboratories using material

and equipment data sheets and test procedures that have been approved by the

Employer. The test procedures shall be formatted as defined in the technical

specifications and shall include a complete list of the applicable reference

standards and submitted for Employer approval at least four (4) weeks before

commencement of test(s). The Contractor shall provide the Employer at least 30

days written notice of the planned commencement of each type test.

(e) The Contractor shall provide a detailed schedule for performing all specified

type tests. These tests shall be performed in the presence of a representative of

the Employer.

(f) The Contractor shall ensure that all type tests can be completed within the time

schedule offered in his Technical Proposal.




(g) In case of failure during any type test, the Supplier is either required to

manufacture a fresh sample lot and repeat all type tests successfully or repeat

that particular type test(s) at least three times successfully on the samples

selected from the already manufactured lot at his own expenses. In case a fresh

lot is manufactured for testing then the lot already manufactured shall be

rejected.

2.1.2 Type Test Samples

The Contractor shall supply equipment/material for sample selection only after the Quality

Assurance Plan has been approved by the Employer. The sample material shall be

manufactured strictly in accordance with the approved Quality Assurance Plan. The

Contractor shall submit for Employer approval, the type test sample selection procedure. The

selection process for conducting the type tests shall ensure that samples are selected at

random. For optical fibres/ Fibre Optic cables, at least three reels/ drums of each type of

fibre/cable proposed shall be offered for selection. For FO cable installation hardware &

fittings at least ten (10) samples shall be offered for selection. For Splice enclosures at least

three samples shall be offered for selection.

2.1.3 List of Type Tests

The type testing shall be conducted on the following items

(a) Optical fibres

(b) OPGW Cable

(c) OPGW Cable fittings

(d) Vibration Damper

(e) Splice Enclosure (Joint Box)

(f) Approach Cable

2.1.3.1 Type Tests for Optical Fibres

The type tests listed below in table 2-1 shall be conducted on DWSM fibres to be supplied as

part of overhead cables. The tests specific to the cable type are listed in subsequent sections.

Table 2-1

Type Tests For Optical Fibres

S. No.

Test Name

Acceptance Criteria

Test procedure

1

Attenuation

As per Section-01 of TS

IEC 60793-1-40

Or EIA/TIA 455-78A

2 Attenuation Variation with Wavelength


IEC 60793-1-40

Or EIA/TIA 455-78A




Table 2-1 Type Tests For Optical Fibres

S. No.

Test Name

Acceptance Criteria

Test procedure

3

Attenuation at Water Peak








IEC 60793-1-40

Or EIA/TIA 455-78A

4 Temp. Cycling (Temp dependence of Attenuation)

IEC 60793-1-52

Or EIA/TIA 455-3A, 2 cycles

5

Attenuation With Bending (Bend Performance)

IEC 60793-1-47

Or EIA/TIA 455-62A

6 Mode Field dia.

IEC 60793-1-45 Or EIA/TIA 455- 164A/167A/174

7

Chromatic Dispersion

IEC 60793-1-42 Or EIA/TIA 455- 168A/169A/175A

8

Cladding Diameter

IEC 60793-1-20 Or EIA/TIA 455-176

9

Point Discontinuities of attenuation

IEC 60793-1-40 Or EIA/TIA 455-59

10

Core -Clad concentricity error

IEC 60793-1-20 Or EIA/TIA 455-176

11

Fibre Tensile Proof Testing


IEC 60793-1-30

Or EIA/TIA 455-31B

-End Of table-

2.1.3.2 Type Tests for OPGW Cables

The type tests to be conducted on the OPGW cable are listed in Table 2-2 Type Tests for

OPGW Cables. Unless specified otherwise in the technical specifications or the referenced

standards, the optical attenuation of the specimen, measured during or after the test as

applicable, shall not increase by more than 0.05 dB/Km.

Table 2-2 Type tests for OPGW Cable

S. No.

Test Name

Test

Description

Test Procedure

1

Water Ingress Test

IEEE 1138-2009

IEEE 1138-2009 (IEC 60794-1-2 Method F5 or EIA/TIA 455-82B) : Test duration : 24 hours




Table 2-2

Type tests for OPGW Cable

S. No.

Test Name

Test Description

Test Procedure

2

Seepage of filling compound

IEEE 1138-2009

IEEE 1138-2009 (EIA/TIA 455-81B)

Preconditioning period:72 hours.

Test duration: 24 hours.

3 Short Circuit Test

IEEE 1138-2009

IEEE 1138-2009

Fibre attenuation shall be continuously monitored and recorded through a digital data logging system or equivalent means. A suitable temperature sensor such as thermocouple shall be used to monitor and record the temperature inside the OPGW tube in addition to monitoring & recording the temperatures between the strands and between optical tube and the strand as required by IEEE 1138. Test shall be conducted with the tension clamps proposed to be supplied. The cable and the clamps shall be visually inspected for mechanical damage and photographed after the test.

Or

IEC60794-4-10 /

IEC 60794-1-2 (2003)

Method H1

Initial temperature during the test shall be greater than or equal to ambient field temperature.

4

Aeolian Vibration Test

IEEE 1138-2009

Or

IEC60794-4-10 /

IEC 60794-1-2, Method E19

IEEE 1138-2009

Fibre attenuation shall be continuously monitored and recorded through a digital data logging system or equivalent means. The vibration frequency and amplitude shall be monitored and recorded continuously. All fibres of the test cable sample shall be spliced together in serial for attenuation monitoring. Test shall be conducted with the tension/suspension clamps proposed to be




Table 2-2


S. No.

Test Name

Test Description

Test Procedure

supplied. The cable and the clamps shall be visually inspected for mechanical damage and photographed after the test.

5

Galloping test

IEEE 1138-2009

IEEE 1138-2009

Test shall be conducted with the tension/suspension clamps proposed to be supplied. The cable and clamps shall be visually inspected for mechanical damage and photographed after the test. All fibres of the test cable sample shall be spliced together in serial for attenuation monitoring.

6

Cable Bend Test

Procedure 2 in IEC 60794-1-2 Method E11

The short-term and long-term bend tests shall be conducted in accordance with Procedure 2 in IEC 60794-1-2 E11 to determine the minimum acceptable radius of bending without any increase in attenuation or any other damage to the fibre optic cable core such as bird caging, deformation, kinking and crimping.

7

Sheave Test

IEEE 1138-2009 OR IEC 60794-1-2 (2003)

Method E1B

IEEE 1138-2009

Fibre attenuation shall be continuously monitored and recorded through a digital data logging system or equivalent means. The Sheave dia. shall be based on the pulling angle and the minimum pulley dia employed during installation. All fibres of the test cable sample shall be spliced together in serial for attenuation monitoring.

8 Crush Test

IEEE 1138-2009

IEEE 1138-2009 (IEC 60794-1-2, Method E3/

The crush test shall be carried out on a sample of approximately one (1) metre long in accordance with IEC 60794-1-2 E3. A load equal




Table 2-2


S. No.

Test Name

Test Description

Test Procedure

EIA/TIA 455-41B)

to 1.3 times the weight of a 400-metre length of fibre optic cable shall be applied for a period of 10 minutes. A permanent or temporarily increase in optical attenuation value greater than 0.1 dB change in sample shall constitute failure. The load shall be further increased in small increments until the measured attenuation of the optical waveguide fibres increases and the failure load recorded along with results.

9

Impact Test

IEEE 1138-2009

IEEE 1138-2009, (IEC 60794-1-2 E4/ EIA/TIA 455-25B)

The impact test shall be carried out in accordance with IEC 60794-1-2 E4. Five separate impacts of 0.1-0.3kgm shall be applied. The radius of the intermediate piece shall be the reel drum radius ± 10%. A permanent or temporary increase in optical attenuation value greater than 0.1 dB/km change in sample shall constitute failure.

10

Creep Test

IEEE 1138-2009

IEEE 1138-2009

As per Aluminium Association Method, the best-fit straight line shall be fitted to the recorded creep data and shall be extrapolated to 25 years. The strain margin of the cable at the end of 25 years shall be calculated. The time when the creep shall achieve the strain margin limits shall also be calculated.

11

Fibre Strain Test

IEEE 1138-1994

IEEE 1138-1994

12

Strain Margin Test

IEEE 1138-2009

IEEE 1138-2009




Table 2-2


S. No.

Test Name

Test Description

Test Procedure

13

Stress strain Test

IEEE 1138-2009

IEEE 1138-2009

14

Cable Cut-off wavelength Test

IEEE 1138-1994

IEEE 1138-1994

15

Temperature Cycling Test

IEEE 1138-2009

IEEE 1138-2009 Or IEC 60794-1-2, Method F1

16

Corrosion (Salt Spray) Test

EIA/TIA 455-16A

17

Tensile Performance Test

IEC 60794-1-2 E1 / EIA/TIA 455-33B

The test shall be conducted on a sample of sufficient length in accordance with IEC 60794-1-2 E1. The attenuation variation shall not exceed 0.05 dB/Km up to 90% of RTS of fibre optic cable. The load shall be increased at a steady rate up to rated tensile strength and held for one (1) minute. The fibre optic cable sample shall not fail during the period. The applied load shall then be increased until the failing load is reached and the value recorded.

18

Lightning Test

IEC 60794-4-10 / IEC 60794-1-2 (2003)

The OPGW cable construction shall be tested in accordance with IEC 60794-1-2, Method H2 for Class 1.

19

DC Resistance Test

(IEC 60228)

On a fibre optic cable sample of minimum 1 metre length, two contact clamps shall be fixed with a predetermined bolt torque. The resistance shall be measured by a Kelvin double bridge by placing the clamps initially zero metre and subsequently one metre apart. The tests shall be repeated at least five times and the average value recorded after correcting at 20°C.

-End Of Table-




2.1.3.3 Type Test on OPGW Cable Fittings

The type tests to be conducted on the OPGW Cable fittings and accessories are listed below: (i) Mechanical Strength Test for Suspension/Tension Assembly Applicable Standards: IEC 61284, 1997. Suspension Assembly

The armour rods /reinforcement rods are assembled on to the approved OPGW using the

Installation Instructions to check that the assembly is correctly fitted and is the same that will

be carried out during installations.

Part 1:

The suspension assembly shall be increased at a constant rate up to a load equal to 50% of

the specified minimum Failure Load increased and held for one minute for the test rig to

stabilise. The load shall then be increased at a steady rate to 67% of the minimum Failure

Load and held for five minutes. The angle between the cable, the Suspension Assembly and

the horizontal shall not exceed 16o. This load shall then be removed in a controlled manner

and the Protection Splice disassembled. Examination of all the components shall be made

and any evidence of visual deformation shall be documented.

Part 2:

The Suspension clamp shall then be placed in the testing machine. The tensile load shall

gradually be increased up to 50% of the specified Minimum Failure Load of the Suspension

Assembly and held for one minute for the Test Rig to stabilise and the load shall be further

increased at a steady rate until the specified minimum Failure Load is reached and held for

one minute. No fracture should occur during this period. The applied load shall then be

increased until the failing load is reached and the value shall be documented.

Tension Assembly

The Tension Assembly is correctly fitted and is the same that will be carried out during

installations.

Part 1:

The tension assembly (excluding tension clamp) shall be increased at a constant rate up to a

load equal to 50% of the specified minimum Failure Load increased at a constant rate and

held for one minute for the test rig to stabilise. The load shall then be increased at a steady

rate to 67% of the minimum Failure Load and held for five minutes. This load shall then

remove in a controlled manner and the Tension Assembly disassembled. Examination of the

Tension Dead-End and associated components shall be made and any evidence of visual

deformation shall be documented.

Part 2:

The Tension Dead-End and associated components shall then be reassembled and bolts




tightened as before. The tensile load shall gradually be increased up shall gradually be

increased up to 50% of the specified Minimum Failure Load of the Tension Assembly and

held for one minute for the Test Rig to stabilise and the load shall be further increased at a

steady rate until the specified minimum Failure Load is reached and held for one minute. No

fracture should occur during this period. The applied load shall then be increased until the

failing load is reached and the value shall be documented.

Acceptance Criteria for Tension/Suspension Assembly: - No evidence of binding of the Nuts or Deformation of components at end of Part 1 of Test. - No evidence of Fracture at the end of one minute at the minimum failure load during Part 2 of the Test. Any result outside these parameters shall constitute a failure. (ii) Clamp Slip Strength Test for Suspension Assembly

The suspension assembly shall be vertically suspended by means of a flexible attachment. A

suitable length fibre optical cable shall be fixed in the clamps. Once the Suspension Clamp

has been assembled, the test rig is tensioned to 1 kN and the position scale on the recorder

‘zeroed’. The test rig is then tensioned to 2.5 kN and the relative positions of the Reinforcing

Rods, Armour Rods and Suspension Clamp shall be marked by a suitable means to confirm

any slippage after the test has been completed. The relative positions of the helical Armour

Rods and associated Reinforcing Rods at each end shall be marked and also 2 mm relative

position between clamp body and Armour Rods shall be marked on one side. The load shall

be increased to 12 kN at a loading rate of 3 kN/min and held for one minute. At the end of

this one minute period, the relative displacement between clamp body and the armour rods

shall be observed. If the slippage is 2 mm or above, the test shall be terminated. Otherwise, at

the end of one minute the position of the clamp body and 2 mm. relative positions between

clamp body and armour rods shall be marked on the other side. After the one minute pause,

the load shall be further increased at a loading rate of 3 kN/min, and recording of load and

displacement shall continue until either the relative Position displacement between clamp

body and armour rods reaches more than 2 mm or the load reaches the maximum slip load of

17 kN. On reaching either of the above values the test is terminated. Visual examination of

all paint marks shall be recorded, and a measurement of any displacement recorded in the

Table of Results. Acceptance Criteria:

The Suspension Clamp has passed the Slip Test if the following conditions are met:

No slippage* shall occur at or below the specified minimum slip load.

* Definition of no slippage in accordance with IEC 61284, 1997:- Any relative

movement less than 2 mm is accepted. The possible couplings or elongations produced

by the cable as a result of the test itself are not regarded as slippage.

Slippage shall occur between the specified maximum and minimum slip load of 12 -

17 kN.




There shall be no slippage of the Reinforcing Rods over the cable, and no slippage of

the Armour Rods over the Reinforcing Rods.

The relative movement (i.e. more than 2 mm between Armour Rods & Clamp body)

between minimum 12 kN and maximum slip 17 kN, shall be considered as slip.

The Armour Rods shall not be displaced from their original lay or damaged**.

** Definition of no damage in accordance with convention expressed in IEC 61284:

1997 no damage, other than surface flattening of the strands shall occur.

Any result outside these parameters is a failure.

(iii) Slip Strength Test of Tension Clamp

Tension clamps shall be fitted on an 8 m length of fibre optic cable on both ends. The

assembly shall be mounted on a tensile testing machine and anchored in a manner similar to

the arrangement to be used in service. A tensile load shall gradually be applied up to 20 % of

the RTS of OPGW. Displacement transducers shall be installed to measure the relative

movement between the OPGW relative to the Reinforcing Rods and Tension Dead -End

relative to Reinforcing Rods. In addition, suitable marking shall be made on the OPGW and

Dead-End to confirm grip. The load shall be gradually increased at a constant rate up to 50 %

of the UTS and the position scale of the recorder is zeroed. The load shall then gradually

increased up to 95 % of the UTS and maintained for one minute. After one minute pause, the

load shall be slowly released to zero and the marking examined and measured for any relative

movement.

Acceptance Criteria:

- No movement* shall occur between the OPGW and the Reinforcing Rods, or between the

Reinforcing Rods and the Dead-End assembly.

- No failure or damage or disturbance to the lay of the Tension Dead-End, Reinforcing Rods

or OPGW.

* Definition of no movement as defined in IEC 61284: Any relative movement less than 2

mm is accepted. The possible couplings or elongations produced by the conductor as a result

of the test itself are not regarded as slippage.

Any result outside these parameters shall constitute a failure.

(iv) Grounding Clamp and Structure Mounting Clamp Fit Test

For structure mounting clamp, one series of tests shall be conducted with two fibre optic

cables installed, one series of tests with one fibre optic cable installed in one groove, and one

series of tests with one fibre optic cable in the other groove. Each clamp shall be installed




including clamping compound as required on the fibre optic cable. The nut shall be tightened

on to the bolt by using torque wrench with a torque of 5.5 kgm or supplier's recommended

torque and the tightened clamp shall be held for 10 minutes. After the test remove the fibre

optic cable and examine all its components for distortion, crushing or breaking. Also the fibre

optic cable shall be checked to ensure free movement within the core using dial callipers to

measure the diameter of the core tube. The material shall be defined as failed if any visible

distortion, crushing, cracking or breaking of the core tube is observed or the fibre optic cable

within the core tube is not free to move, or when the diameter of the core tube as measured at

any location in the clamped area is more than 0.5 mm larger or smaller of the core diameter

as measured outside the clamped area.

(v) Structure Mounting Clamp Strength Test

The clamp and mounting assembly shall be assembled on a vertical 200 mm x 200 mm angle

and a short length of fibre optic cable installed. A vertical load of 200 kg shall be applied at

the end of the mounting clamp and held for 5 minutes. Subsequently, the load shall be

increased to 400 kg and held for 30 seconds. Any visible distortion, slipping or breaking of

any component of the mounting clamp or assembly shall constitute failure.

2.1.3.4 Type Test on Vibration Damper

The testing standard of vibration damper for OPGW shall be as per applicable international

standard i.e. IEC 61897.

(a) Dynamic Characteristic Test

The damper shall be mounted with its clamp tightened with torque recommended by the

manufacturer on shaker table capable of simulating sinusoidal vibrations for Critical Aeolian

Vibration frequency band ranging from 0.18/d to 1.4/d – where d is the OPGW cable

diameter in meters. The damper assembly shall be vibrated vertically with a ±1 mm

amplitude from 5 to 15 Hz frequency and beyond 15 Hz at 0.5 mm to determine following

characteristics with the help of suitable recording instruments.

(i) Force Vs frequency

(ii) Phase angle Vs frequency

(iii) Power dissipation Vs frequency

The Force Vs frequency curve shall not show steep peaks at resonance frequencies and deep

troughs between the resonance frequencies. The resonance frequencies shall be suitably

spread within the Aeolian vibration frequency-band between the lower and upper dangerous

frequency limits determined by the vibration analysis of fibre optic cable without dampers.

Acceptance criteria for vibration damper:

(i) The above dynamic characteristics test on five damper shall be conducted.




(ii) The mean reactance and phase angle Vs frequency curves shall be drawn with

the criteria of best fit method.

(iii) The above mean reactance response curve should lie within following limits:

V.D. for OPGW - 0.060 f to 0.357 f kgf/mm*

Where f is frequency in Hz.

(iv) The above mean phase angle response curve shall be between 25o to 130

o

within the frequency range of interest.

(v) If the above curve lies within the envelope, the damper design shall be

considered to have successfully met the requirement.

(vi) Visual resonance frequencies of each mass of damper is to be recorded and to

be compared with the guaranteed values.

(b) Vibration Analysis

The vibration analysis of the fibre optic cable shall be done with and without damper

installed on the span. The vibration analysis shall be done on a digital computer using energy

balance approach. The following parameters shall be taken into account for the purpose of

analysis.

(i) The analysis shall be done for single fibre optic cable without armour rods. The

tension shall be taken as 25% of RTS of fibre optic cable for a span ranging

from 100 m to 1100 m.

(ii) The self damping factor and flexural stiffness (EI) for fibre optic cable shall be

calculated on the basis of experimental results. The details to experimental

analysis with these data shall be furnished.

(iii) The power dissipation curve obtained from Damper Characteristics Test shall

be used for analysis with damper.

(iv) Examine the Aeolian Vibration level of the fibre optic cable with and without

vibration damper installed at the recommended location or wind velocity

ranging from 0 to 30 Km per hour, predicting amplitude, frequency and

vibration energy input.

(v) From vibration analysis of fibre optic cable without damper, antinode vibration

amplitude and dynamic strain levels at clamped span extremities as well as

antinodes shall be examined and thus lower and upper dangerous frequency

limits between which the Aeolian vibration levels exceed the specified limits

shall be determined.

(vi) From vibration analysis of fibre optic cable with damper(s) installed at the

recommended location, the dynamic strain level at the clamped span extremities,

damper attachment point and the antinodes on the fibre optic cable shall be




determined. In addition to above damper clamp vibration amplitude and

antinodes vibration amplitudes shall also be examined.

The dynamic strain levels at damper attachment point, clamped span extremities

and antinodes shall not exceed the specified limits. The damper clamp vibration

amplitude shall not be more than that of the specified fatigue limits.

(c) Fatigue Tests

(i) Test Set Up

The fatigue tests shall be conducted on a laboratory set up with a minimum effective span

length of 30m. The fibre optic cable shall be tensioned at 25% of RTS of fibre optic cable and

shall not be equipped with protective armour rods at any point.

Constant tension shall be maintained within the span by means of lever arm arrangement.

After the fibre optic cable has been tensioned, clamps shall be installed to support the fibre

optic cable at both ends and thus influence of connecting hardware fittings are eliminated

from the free span. The clamps shall not be used for holding the tension on the fibre optic

cable. There shall be no loose parts, such as suspension clamps, U bolts, on the test span

supported between clamps mentioned above. The span shall be equipped with vibration

inducing equipment suitable for producing steady standing vibration. The inducing

equipment shall have facilities for step less speed control as well as step less amplitude

arrangement. Equipment shall be available for measuring the frequency, cumulative number

of cycles and amplitude of vibration at any point along the span.

(ii) Fatigue Test

The vibration damper shall be installed on the test span with the manufacturer's specified

tightening torque. It shall be ensured that the damper shall be kept minimum three loops away

from the shaker to eliminate stray signals influencing damper movement.

The damper shall then be vibrated at the highest resonant frequency of each damper mass.

For dampers involving torsional resonant frequencies, tests shall be done at torsional modes

also in addition to the highest resonant frequencies at vertical modes. The resonance

frequency shall be identified as the frequency at which each damper mass vibrates with the

maximum amplitude on itself. The amplitude of vibration of the damper clamp shall be

maintained not less than ±25/f mm where f is the frequency in Hz.

The test shall be conducted for minimum ten million cycles at each resonant frequency

mentioned above. During the test, if resonance shift is observed, the test frequency shall be

tuned to the new resonant frequency.

The clamp slip test as mentioned herein shall be repeated after fatigue tests without

retorquing or adjusting the damper clamp, and the clamp shall withstand a minimum load

equal to 80% of the slip strength for a minimum duration of one minute.




After the above tests, the damper shall be removed from fibre optic cable and subjected to

dynamic characteristics test. There shall not be any major deterioration in the characteristics

of the damper. The damper then shall be cut open and inspected. There shall not be any

broken, loose, or damaged part. There shall not be significant deterioration or wear of the

damper. The fibre optic cable under clamp shall also be free from any damage.

For purposes of acceptance, the following criteria shall be applied:

(1) There shall not be any resonant frequency shift before and after the test by

more than ± 20%

(2) The power dissipation of the damper before and after test at the individual

resonant frequencies do not differ by more than ± 20%

Beside above tests, the type tests listed below in the table shall also be conducted on

Vibration Damper

Sl

No.

Test Name Test Procedure

1 Visual examination & Dimensional and


IEC 61897 Clause 7.1 & 7.2

2 Clamp Slip test IEC 61897 Clause 7.5

3 Clamp bolt tightening test IEC 61897 Clause 7.7

4 Attachments of weights to messenger

cable

IEC 61897 Clause 7.8

5 Attachment of clamps to messenger

cable

IEC 61897 Clause 7.8

6 Damper effectiveness evaluation IEC 61897 Clause 7.11.3.2

2.1.3.5 Type Tests for Splice Enclosures (Joint Box)

Following Type tests shall be demonstrated on the Splice Enclosure(s) (Splice

Enclosure/Box). For certain tests, lengths of the fibre optic cable shall be installed in the

splice box, and the fibres must be spliced and looped in order to simulate conditions of use.

The attenuation of the fibres shall be measured, during certain tests, by relevant Fibre Optic

Test Procedures (EIA/TIA 455 or IEC 60794-1 procedures).

(i) Temperature Cycling Test

FO cable is installed in the splice enclosure and optical fibres spliced and looped. The box

must be subjected to 5 cycles of temperature variations of -40C to +65C with a dwell time

of at least 2 hours on each extreme.

Fibre loop attenuation shall be measured in accordance with EIA 455-20 / IEC 60794-1-C10.

The variation in attenuation shall be less than ±0.05dB. The final humidity level, inside the




box, shall not exceed the initial level, at the closing of the box.

(ii) Humid Heat test

The sealed splice enclosure, with fibres spliced and looped inside, must be subjected to a

temperature of +55C ±2C with a relative humidity rate of between 90% and 95% for 5

days. The attenuation variation of the fibres during the duration of the test shall be less than

±0.05dB, and the internal humidity rate measured, less than 2%.

(iii) Rain Withstand Test / Water Immersion test

The splice enclosure with optical fibres cable installed and fibres spliced fixed, shall be

subjected to 24 hours of simulated rain in accordance with IEC 60060 testing requirements.

No water seepage or moisture shall be detected in the splice enclosure. The attenuation

variation of the fibres after the test shall be less than ±0.05dB.

(iv) Vibration Test

The splice enclosure, with fibres united inside, shall be subjected to vibrations on two axes

with a frequency scanning of 5 to 50 Hz. The amplitude of the vibrations shall be constant at

0.450mm, peak to peak, for 2 hours, for each of the vibrations' axes. The variation in

attenuation, of the fibres, shall be less than ±0.05dB. The splice enclosure shall be examined

for any defects or deformation. There shall be no loosening or visible damage of the FO cable

at the entry point.

(v) Bending and Torsion test

The splice enclosure, with fibres spliced inside, shall be firmly held in place and be subjected

to the following sequence of mechanical stresses on the cable:

a) 3 torsion cycles of ±180 shall be exercised on the cable. Each cycle shall be less than

one minute.

b) 3 flexure cycles of the cable, of ±180 with one cycle less than one minute.

The variation in the attenuation, of the fibres, shall be less than ±0.05dB. The cables

connection ring shall remain securely fixed to the box with the connection maintained firmly.

No defects/fissures shall be noted on the joint ring or on the splice enclosure

(vi) Tensile test

The splice enclosure with cable fixed to the boxes shall be subjected to a minimum tension of

448 N for a period of two minutes. No fissure shall be noted in the connections or on the

box.

(vii) Drop Test




With 2 lengths of 11 metres of cable fixed to the box, it shall be dropped five times from a

height of 10 metres. There shall be no fissure, at all, of the box, and the connections shall

remain tight. The test surface shall be carried out in accordance with IEC 60068-2-32.

2.1.3.6 Type Tests for Fibre Optic Approach Cable The type tests to be conducted on the Fibre Optic Approach cable are listed in Table 2-3: Type Tests for Fibre Optic Approach Cable. Unless specified otherwise in the technical specifications or the referenced standards, the optical attenuation of the specimen, measured during or after the test as applicable, shall not increase by more than 0.05 dB/Km.

Table 2-3: Type Tests Fibre Optic Approach Cable

S.NO.

Test Name

Test Procedure

1

Water Ingress Test

(IEC 60794-1-F5 / EIA 455-82B) Test duration : 24 hours

2

Seepage of filling compound

(EIA 455-81A)

Preconditioning : 72 hours,

Test duration : 24 hours.

3 Crush Test

(IEC 60794-1-E3/ EIA 455-41)

4

Impact Test

(IEC-60794-1-E4/ EIA 455-25A)

5

Stress strain Test

(EIA 455-33A)

6

Cable Cut-off wavelength Test

(EIA 455-170)

7

Temperature Cycling Test

(IEC60794-1-F1/EIA-455-3A) – 2 cycles

-End Of Table-

2.1.3.6.1 Impact Test The Impact test shall be carried out in accordance with IEC:60794-1-E4. Five separate impacts of 2.0 kg shall be applied at different locations. The radius of the intermediate piece shall be the reel drum radius ± 10%. A permanent or temporary increase in optical attenuation value greater than 0.05 dB/km shall constitute failure.

2.2 Factory Acceptance Tests

Factory acceptance tests shall be conducted on randomly selected final assemblies of all

equipment to be supplied. Factory acceptance testing shall be carried out on OPGW Cable

and associated hardware & fittings, Approach Cable, Joint Box, FODP etc. and all other

items for which price has been identified separately in the Bid Price Schedules.




Material shall not be shipped to the Employer until required factory tests are completed

satisfactorily, all variances are resolved, full test documentation has been delivered to the

Employer, and the Employer has issued Material Inspection & Clearance Certificate (MICC).

Successful completion of the factory tests and the Employer approval to ship, shall in no way

constitute final acceptance of the system or any portion thereof. These tests shall be carried

out in the presence of the Employer's authorised representatives unless waiver for witnessing

by Employer’s representatives is intimated to the contractor.

Factory acceptance tests shall not proceed without the prior delivery to and approval of all

test documentation by the Employer.

The factory acceptance tests for the supplied items shall be proposed by the Contractor in

accordance with technical specifications and Contractor's (including Sub-Contractor's /

supplier's) standard FAT testing program. In general the FAT for other items shall include at

least: Physical verification, demonstration of technical characteristics, various operational

modes, functional interfaces etc.

For Test equipment FAT shall include supply of proper calibration certificates, demonstration

of satisfactory performance, evidence of correct equipment configuration and manufacturer’s

final inspection certificate/ report.

2.2.1 Sampling for FAT

From each batch of equipment presented by the Contractor for Factory acceptance testing, the

Employer shall select random sample(s) to be tested for acceptance. Unless otherwise agreed,

all required FAT tests in the approved FAT procedures, shall be performed on all samples.

The Sampling rate for the Factory acceptance tests shall be minimum 10% of the batch size

(minimum 1) for all items. The physical verification shall be carried out on 100% of the

offered quantities as per the approved FAT procedure. In case any of the selected samples

fail, the failed sample is rejected and additional 20% samples shall be selected randomly and

tested. In case any sample from the additional 20% also fails the entire batch may be

rejected.

For the OPGW cable hardware fittings & accessories, the minimum sampling rate, and batch

acceptance criteria shall be as defined in IS 2486.

The Sampling rate for the Factory acceptance tests shall be 10% of the batch size (minimum

2) for FO cable drums, FODPs, Joint box and other similar items.

Since FAT testing provides a measure of assurance that the Quality Control objectives are

being met during all phases of production, the Employer reserves the right to require the

Contractor to investigate and report on the cause of FAT failures and to suspend further

testing/ approvals until such a report is made and remedial actions taken, as applicable.




2.2.2 Production Testing

Production testing shall mean those tests which are to be carried out during the process of

production by the Contractor to ensure the desired quality of end product to be supplied by

him. The production tests to be carried out at each stage of production shall be based on the

Contractor’s standard quality assurance procedures. The production tests to be carried out

shall be listed in the Manufacturing Quality Plan (MQP), alongwith information such as

sampling frequency, applicable standards, acceptance criteria etc.

The production tests would normally not be witnessed by the Employer. However, the

Employer reserves the right to do so or inspect the production testing records in accordance

with Inspection rights specified for this contract.

2.2.3 Factory Acceptance Tests on Optical Fibre to be supplied with OPGW

The factory acceptance tests listed in table below are applicable for the Optical fibres to be supplied. The listed tests follow testing requirements set forth in IEEE standard 1138/IEC 60794. The referenced sections specify the detailed test description. The acceptance norm shall be as specified in the above mentioned IEEE standards unless specified otherwise in the technical specifications.

Table 2-4

Factory Acceptance Tests for Optical Fibres: Optical Tests S. No.

Test Name

Acceptance Criteria

Test procedure

1

Attenuation Coefficient

T S,Table 1-1(a)

EIA/TIA 455- 78A

2

Point Discontinuities of attenuation

TS, Section 1.1.2

EIA/TIA 455-59

3

Attenuation at Water Peak

TS ,Table 2-1(a)

EIA/TIA 455- 78A

4

Chromatic Dispersion

EIA/TIA 455- 168A/169A/175A

5

Core – Clad Concentricity Error

EIA/TIA 455-/176

6

Cladding diameter

EIA/TIA 455-176

7

Fibre Tensile Proof Testing

EIA/TIA 455-31B

-End of table-

The test report for the above tests for the fibers carried out by the Fiber Manufacturer and

used in the OPGW cables shall be shown to the inspector during OPGW cable FAT and shall

be submitted along with the OPGW cable FAT report.

2.2.4 Factory Acceptance Test on OPGW Cable




The factory acceptance tests for OPGW cable specified below in Table follow the

requirements set forth in IEEE standard 1138 / IEC 60794. The FAT shall be carried out on

10% of offered drums in each lot as specified in technical specifications and the optical tests

shall be carried out in all fibres of the selected sample drums. The Rated Tensile Strength test

shall be carried out on one sample in each lot.

Table 2-5

Factory Acceptance Tests on OPGW Applicable standard: IEEE 1138 / IEC 60794

S.

No.

Factory Acceptance Test on Manufactured OPGW

1

Attenuation Co-efficient at 1310 nm and 1550 nm

2

Point discontinuities of attenuation

3

Visual Material verification and dimensional checks as per approved DRS/Drawings

4

Rated Tensile Strength

5

Lay Length Measurements

2.2.5 Factory Acceptance Test on OPGW Fittings

The factory acceptance tests for OPGW Fittings as specified below in Table 2-6. The sampling plan shall be as per relevant standard:

Table 2-6

Factory Acceptance Tests On OPGW Fittings S. No.

Factory Acceptance Test

Suspension Assembly

1

UTS/Mechanical Strength of the assembly

2

Clamp Slip Test

3


4 Mechanical strength of each component

5 Galvanising test

Tension Assembly

6 Clamp Slip Strength test

7


8 Mechanical strength of each component

9 Galvanising Test




Table 2-6

Factory Acceptance Tests On OPGW Fittings S. No.


Vibration Damper

10 Galvanising test on damper, masses and messenger wires

11

Damper response (resonant frequencies)

12

Clamp Slip test

13

Strength of messenger wires

14 Attachments of weights to messenger cable

15

Attachments of clamps to messenger cable

16

Clamp bolt tightening test

17 Clamp bolt torque test

18 Dynamic characteristic test.

19


Structure Mounting Clamp

20 Clamp fit test

21 Clamp Strength test

22


End of Table

2.2.6 Factory Acceptance Test on Approach Cable

The factory acceptance tests for Approach Cable specified below in Table 2-7:

Table 2-7

Factory Acceptance Tests On Approach Cable S. No.


1

Attenuation Co-efficient at 1310 nm and 1550 nm

2

Point discontinuities of attenuation

3





2.2.7 Factory Acceptance Test on Splice Enclosure (Joint Box) /FODP

The factory acceptance tests for Splice Enclosures/FODP as specified below in Table: 2-8

Table 2-8

Factory Acceptance Tests on Splice Enclosures (Joint Box)/FODP S. No.


1

Visual check of Quantities and Specific Component Number for each component

of Splice Enclosure/FODP and dimensional checks against the approved drawings.

2.2.8 Factory Acceptance Test on Test Equipment & other items

As per technical specification and approved DRS/Documents.

2.3 Site Acceptance Tests

The Contractor shall be responsible for the submission of all material & test equipment

supplied in this contract for site tests and inspection as required by the Employer. All

equipment shall be tested on site under the conditions in which it will normally operate.

The tests shall be exhaustive and shall demonstrate that the overall performance of the

contract works satisfies every requirement specified. At a minimum Site Acceptance Testing

requirement for FO cable etc. is outlined in following section. This testing shall be

supplemented by the Contractor's standard installation testing program, which shall be in

accordance with his quality plan(s) for FO installation.

During the course of installation, the Employer shall have full access for inspection and

verification of the progress of the work and for checking workmanship and accuracy, as may

be required. On completion of the work prior to commissioning, all equipment shall be tested

to the satisfaction of the Employer to demonstrate that it is entirely suitable for commercial

operation.

2.3.1 Minimum Site Acceptance Testing Requirement for FO Cabling

Prior to installation, every spooled fibre optic cable segment shall be tested for compliance

with the Pre-shipment data previously received from the manufacturer. This requirement will

preclude the installation of out of specification cable segments that may have been damaged

during shipment.




2.3.1.1 Phases of Site Acceptance Testing

SAT shall be carried out link by link from FODP to FODP. SAT may be performed in parts

in case of long links.

The tests, checks, adjustments etc conducted by the Contractor prior to offering the

equipment for SAT shall be called Pre-SAT activities. The Pre-SAT activities shall be

described in the installation manuals and Field Quality Plan documents.

Sag and tension of OPGW shall generally be as per approved sag-tension chart and during

installation, sag and tension of OPGW shall be documented. Upon completion of a

continuous cable path, all fibres within the cable path shall be demonstrated for acceptance of

the cable path. Fibre Optic cable site testing minimum requirements are provided in Table 2-

9(a) through 2-9(c) below:

Table 2-9(a)

Fibre Optic Cable Pre-Installation Testing

Item:

Description:

1. Physical Inspection of the cable assembly for damage

2.

Optical fibre continuity and fibre attenuation with OTDR at 1550 nm

3.

Fibre Optic Cable length measurement using OTDR

Table 2-9(b)

Fibre Optic Cable Splicing Testing

Item:

Description:

1. Per splice bi-directional average attenuation with OTDR

2.

Physical inspection of splice box/enclosure for proper fibre / cable routing

techniques

3. Physical inspection of sealing techniques, weatherproofing, etc.

Table 2-9(c)

Fibre Optic Cable Commissioning Testing Item:

Description:

1.

End to End (FODP to FODP) bi-directional average attenuation of each fibre at

1310 nm and 1550 nm by OTDR. End to End (FODP to FODP) bi-directional average attenuation of each fibre at




2. 1310 nm and 1550 nm by Power meter.

3. Bi-directional average splice loss by OTDR of each splice as well as for all

splices in the link (including at FODP also).

4. Proper termination and labelling of fibres & fibre optic cables at FODP as per

approved labelling plan.

-End of Table-

----------------------------------------------End of this Section-------------------------------------------



Section-IX -Chapter-03 Page 1 of 4

Chapter-03

Installation for OPGW Cabling

Table of Content

3.1 Installation requirements .............................................................................................. 2

3.1.1 Installation of OPGW cable .......................................................................................... 2

3.1.2 Installation Hardware fittings ....................................................................................... 2

3.2 Installation of Approach cable ....................................................................................... 2

3.3 Optical fibre termination and splicing ............................................................................ 3

3.4 Fibre Optic Distribution Panel....................................................................................... 3

3.5 Methodology for installation and termination .................................................................. 3

3.6 Cable raceways ............................................................................................................ 4




Section-03

Installation of OPGW Cabling

3.1 Installation requirements

The OPGW cable shall be installed at the top of the tower in place of earthwire (only one of the

earthwire peaks in case of 400kV & above lines, if applicable) for under construction transmission

lines as envisaged.

The OPGW cable sections shall normally be terminated & spliced only on tension towers. In

exceptional circumstances, and on Employer specific approval, cable may be terminated on suspension

towers, but in this case tower strength shall be examined to ensure that tower loads are within safe

limits and if required, necessary tower strengthening shall be carried out by the Contractor.

For OPGW Cable to be installed on new line transmission line, the stringing shall be carried by the

Transmission Line Contractor as per the stringing chart/procedure submitted by them and approved by

Employer. The Contractor shall install OPGW as per approved stringing procedure.

The Contractor shall follow precautions including proper location of drum site, installation of stringing

blocks/pulleys, proper sagging, proper installation of hardware, proper tension as per Sag-Tension

chart, provision of service loops of OPGW in jointing locations etc.

3.1.1 Installation of OPGW cable

The OPGW cable sections shall normally be terminated & spliced only on tension towers. In

exceptional circumstances and on Employer specific approval, cable may be terminated on Suspension

towers, but in this case tower strength shall be examined to ensure that tower loads are within safe

limits and if required, necessary tower strengthening shall be carried out by the Contractor. In such a

case, the jointing of OPGW on suspension tower if required, shall be acceptable subject to its

suitability.

3.1.2 Installation Hardware Fittings

All required hardware fittings shall be installed alongwith OPGW Cable.

3.2 Installation of Approach Cable

The existing cable trenches/ cable raceways proposed to be used shall be identified in the survey

report. The Contractor shall make its best effort to route the cable through the existing available cable

trenches. Where suitable existing cable trenches are not available, suitable alternatives shall be

provided after Employer approval. However, the approach cable shall be laid in the HDPE pipe in all

condition.




Suitable provisions shall be made by the Contractor to ensure adequate safety earthing and insulated

protection for the approach cable.

All required fittings, supports, accessories, ducts, inner ducts, conduits, risers and any item not

specially mentioned but required for laying and installation of approach cables shall be supplied and

installed by the Contractor.

3.3 Optical Fibre Termination and Splicing

Optical fibre terminations shall be installed in Fibre Optic Distribution Panels (FODP) designed to

provide protection for fibre splicing of preconnectorized pigtails and to accommodate connectorized

termination and coupling of the fibre cables. The Contractor shall provide rack /wall mounted Fibre

Optic Distribution Panels (FODPs) sized as indicated in the appendices and shall terminate the fibre

optic cabling up to the FODPs. The location of FODP rack shall be fixed by the Contractor, with the

Employer’s approval.

3.4 Fibre Optic Distribution Panel

At each location requiring the termination of at least one fibre within a cable, all fibres within that

cable shall be connectorized and terminated in Fibre Optic Distribution Panels in a manner consistent

with the following :

(a) All fibre optic terminations shall be housed using FODPs provisioned with splice organizers and

splice trays. All fibres within a cable shall be fusion spliced to pre-connectorized pigtails and

fitted to the "Back-side" of the provided fibre optic couplings.

(b) Flexible protection shall be provided to the patch cord bunches going out from FODP to other

equipment.

3.5 Methodology for Installation and Termination

All optical fibre cable termination, installation, stringing and handling plans, guides and procedures,

and engineering analysis (e.g. tension, sag, vibration etc.) shall be submitted to the Employer for

review and approval in the engineering/design phase of the project, prior to establishing the final cable

lengths for manufacture. Installation procedures including details of personnel and time required shall

be documented in detail and submitted to Employer for approval. All installation practices shall be

field proven and ISO accredited.

All cable segments shall include service loops as specified in this specification .The maximum

allowable stringing tension, maximum allowable torsional shear stress, crush strength and other

physical parameters of the cable shall not be exceeded. The preventative measures to be taken shall be

documented in detail and submitted to Employer in advance of installation.




Optical fibre attenuation shall be measured after installation and before splicing. Any increase in

attenuation or step discontinuity in attenuation shall not be acceptable and shall constitute a cable

segment failure. In the event of cable damage or any fibre damage, the complete section (tension

location to tension location) shall be replaced as mid-span joints are not acceptable.

Any or all additional steel work or modifications required to attach the fibre cabling to the overhead

transmission/ distribution line towers shall also be carried out by the Contractor. It shall be the

Contractors responsibility to provide adequate communications among all crew members and support

staff to ensure safe and successful installations.

3.6 Cable Raceways

To the extent possible, existing cable raceways shall be utilised. The Contractor is required to provide

and install any additional indoor cable raceways which may be required for proper implementation of

the fibre optic cabling system. This requirement shall be finalised during survey. The cable raceways

shall conform to the following:

(a) All cable raceways shall be sized to support full loading requirements plus at least a 200% safety

loading factor.

(b) Indoor cable raceways shall be fabricated from construction grade aluminium, galvanized iron or

anodized sheet metal or any other suitable material approved by the Employer. Suitable anti-

corrosion measures shall be provided. Steel fabricated raceways shall be finished inside and out,

treated to resist rust and to form a metal-to- paint bond.

(c) Mechanical construction drawings of the cable raceways shall be submitted for Employer’s

information & review.

…………………….……..…End of this Section……………………………...


1 Volume II Section XI

SECTION-11

TECHNICAL SPECIFICATION OF

MODULAR EMERGENCY RESTORATION SYSTEM FOR

400 KV TRANSMISSION LINES

(SUITABLE FOR 220 kV AND 132KV TRANSMISSION LINES ALSO

CONTENTS

Clause No. Name of Clause

11.1 SCOPE

11.2 INTERNATIONAL STANDARDS / CODES

11.3 SERVICE CONDITIONS

11.4 DESIGN, CONSTRUCTION AND WORKMANSHIP

11.4.1 DESIGN CRITERIA FOR ERS TOWERS

11.4.2 STRENGTH FACTORS

11.4.3 MODULAR STRUCTURE

11.4.4 FOUNDATION PLATE

11.4.5 ARTICULATED BASE

11.4.6 GUY PLATE & BOX SECTIONS

11.4.7 ANCHORING ASSEMBLY

11.4.8 INSULATORS 11.4.9 GUY WIRES AND GRIPS

11.4.10 CONSTRUCTION TOOLS AND EQUIPMENTS

11.4.11 CONTAINER FOR ERS 11.4.12 COMPUTER SOFTWARE 11.5 OTHER ACCESSORIES AND EQUIPMENT

11.5.1 LAPTOP

11.5.2 WALKIE-TALKIE

11.5.3 PORTABLE DIESEL GENERATOR SET

11.5.4 GPS RECEIVER

11.5.5 TOTAL STATION SURVEYING EQUIPMENT

11.5.6 TRIPOD WITH CHAIN PULLEY BLOCK SYSTEM HAVING CAPACITY TO LIFT 10 MT LOAD

11.5.7 MOTORISED CAPSTAN HOIST HAVING LIFTING/PULLING



CAPACITY OF 10 MT

11.6 INSPECTION AND TEST 11.7 TRAINING TO THE ENGINEERS/TECHNICIANS 11.8 DRAWING AND DOCUMENTATION 11.9 SCHEDULE OF GUARANTEED CHARACTERISTICS FOR

MODULAR ERS WITH ACCESSORIES



SECTION-11


FOR MODULAR EMERGENCY RESTORATION SYSTEM FOR 400 KV TRANSMISSION LINES (SUITABLE FOR 220 kV

AND 132KV TRANSMISSION LINES ALSO)

11.1 SCOPE:

Though the tender is for procurement of ERS for 400KV Transmission Lines, NEA intent to use the same for restoration of 220KV and 132KV transmission lines also besides for restoration of 400KV transmission line. Therefore, the successful bidder will have to supply one set of 400 kV complete emergency restoration system (ERS) conforming to the general and technical parameters specified herein. Each set shall consist of 4 (six) suspension structures of approximately 48 m in height and 2 (two) tension structures with angle upto 60 degree (Design Criteria as given in Table-1 of this section). The emergency restoration system will consist of all necessary re-usable aluminum restoration structures, anchors, hardware, insulators, construction tools, spare parts, computer software and training necessary for restoration of 132KV, 220KV and 400KV transmission line.

ERS shall include the following:

(i) Modular ERS towers/structures, foundation/base plates, guys & guy hardware,

anchor assemblies, (ii) Composite insulators along with hardware fittings, (iii) Tools and tackles and equipment required for erection and stringing. (iv) Computer software for analyzing failure scenarios and identifying appropriate

scheme of ERS deployment, (v) Containers for ERS items (vi) Other items as detailed in Section-11 of Technical specification and Bid proposal

sheets.

Further, the scope of work shall also include training & demonstration as well as preparation and submission of comprehensive installation and maintenance manuals and guidelines for storage, transportation, erection and stringing operation of ERS and associated equipment. The manuals shall be in separate bound volumes and nicely printed in English. Three (3) sets of manuals for each equipment shall be provided.

The scope of work shall also include supply of erection tools & special tools required

for installation of the ERS offered by the bidder.

New Butwal – Bardaghat 220 kV Transmission Line Project (Design, Supply, Construction & Commissioning)


11.2 INTERNATIONAL STANDARDS/CODES :

The material and services under this specification shall be performed as per the requirements of the latest revisions and amendments available at the time of placement of order of all the relevant IEC and IEEE standards, listed here under or equivalent or superior standards shall also be considered.

- IEEE 1070 (2006 or latest): Design and testing of transmission modular

restoration structure Components

- IEEE 135.61-1997: Testing of overhead transmission and distribution line

hardware

- IEC 60652: Loading test on overhead lines structure

- IEC:61466-1 Composite insulator units for overhead lines with a nominal

voltage greater than 1000 V

- IEC 601109 Standard Specification for Composite Insulators for AC Overhead Lines

with Nominal Voltage Greater than 1000 V: Definitions, test methods and acceptance

criteria

- IEC:60852 Loading test on overhead line towers

- IEC:60826 Loading and strength of overhead transmission lines

- ASTM A-153 Standard Specification for Zinc Coating (Hot-Dip) on Iron and Steel

Hardware

- ASTM-A474 Standard Specification for Aluminum-Coated Steel Wire Strand

- ASTM B209 Specification for Aluminum alloy sheet and plate

11.3 SERVICE CONDITION

The emergency restoration towers shall be suitable for continuous operation outdoors at

altitude of up to 3000m above sea level, humidity of up to 95%, average ambient

temperature of +30deg Celsius with a minimum of – 10 0c and maximum 0f +45

oc . The

ERS towers shall be designed to withstand wind speed of up to 47m/sec.

11.4. DESIGN, CONSTRUCTION AND WORKMANSHIP

11.4.1 Design Criteria for ERS Towers

The ERS shall be design to withstand the condition stated in table 1 below



Table -1 Design Criteria for ERS Tower

Description 400kV

Minimum Insulator Length Suspension: 4980 mm

Post: 4106 mm

Minimum creepage distance 9900 mm

Conductor Name ACSR Moose/

Conductor Diameter 31.77 mm

Conductor weight 2.004 kg/m

Conductor Ultimate tensile strength 161. kN

No. of conductors per phase 2

Earth wire Type OPGW

Earth wire diameter 14.25 mm

Earth wire weight 0.6 kg/m

Earth wire ultimate tensile strength 73.6 kN

Phase-to-phase clearance 6.8 m

Minimum Cable to ground clearance at mid span

9.5 m

Minimum Cable height at the tower

27.7 m

Conductor Sag tension at EDT 20%

Wind Velocity 47 m/sec

Ruling Span 400 m

Line angle for suspension towers 0-20°

Line angle for anchor towers 20-60°

Load factors for ERS at vertical and transfer loads

1.1

Gust Respond Factor (GRF) 1.0

EDT Temperature (conductor) 20°C

Wind temperature (conductor) 5°C

Cold Temperature (conductor) 5°C

Hot temperature (conductor) 75°C

Ice Temperature No ice No ice

No ice Ice Thickness

Wind at Ice condition



11.4.2 Strength Factors

The minimum strength factors presented in the table below should be used for each

tower component in order to ensure a safe configuration design.

Table -2 Allowed Percentages of Strength Ratings/Strength Factors

Elements % of Ultimate

Capacity

Reference Standard

Steel guy cables 65% ASCE 10-97 ASCE Manual 72

ASCE Manual 91 Guy strain insulators 65%

Anchors 50%

Hardware (turnbuckle, shackle, etc.)

60% ASCE 10-97 ASCE Manual 74

ASCE Manual 91 Plates and metal rods (aluminum or steel)

60%

Suspension/ strain insulators 50% of SML NESC 2007 ANSI c29.12-1997

ANSI c29.17-2002

ANSI c29.18-2003

Line post insulators – compression

50% of Euler

Line post insulators – Tension 50% of STL

Suspension clamps for cables 60% ASCE 10-97 ASCE Manual 74

ASCE Manual 91 Strain clamps for cables 60%

Guy Plates and simple structural elements

60% ASCE 10-97 ASCE Manual 74

Modules and complex tower components

50%

11.4.3 Modular Structure

The ERS structure shall be made of high strength aluminum alloy and be of modular

construction allowing easy adoption to various line designs / configurations. All

components must be fully exchangeable regardless whether they are used in suspension,

angle or dead end conditions. To ensure uniform compatibility of the ERS supplied

under the contract, all components of modular restoration structures shall be geometrically

identical / mutually compatible.

The mast sections shall be lightweight, made of high strength aluminum alloy. The shape,

size, dimensions and weight of individual components shall be such that manual handling

of the components is possible. NEA requires that the ERS structures shall be designed,

built and be geometrically and dimensionally in accordance with IEEE Std. 1070-2006

“IEEE Guide for the Design and Testing of Transmission Modular Restoration Structure

Components”, the only recognized and acceptable international standard for emergency

restoration structures.

Each ERS column section shall be of a welded aluminum construction, in order to prevent

loss or theft of individual members.

□ The main structure elements shall be made from high strength structural aluminum

alloy in order to reduce weight and prevent corrosion.

□ No structural element shall weigh more than (260 kg.). The structure column section



shall not be more than 4.2m (14 feet) in length. Also, weight of the structure column

section shall not exceed 200 kgs. The weight of any other individual component of

ERS shall not exceed 260 kgs.

□ Only one size (diameter and length) of threaded fastener shall be used to assemble

the ERS structural elements.

□ The ERS column sections shall be large enough to allow up to four (4) linemen to work

with ease at one elevation at one time.

□ The angle bracing that the linemen stands on shall be a flat surface not less than

(50mm) in width.

□ The ERS structure elements shall be of a robust design to prevent damage during

expected rough field handling during emergency conditions. In order to insure this, no

structural member shall have a thickness less than 0.25in.

□ Each column section shall be proof tested for minimum specified strength, and tested

for accuracy of mating and alignment holes.

NEA requires that the ERS structures shall be designed, built and be geometrically in

accordance with IEEE Std. 1070-2006 “IEEE Guide for the Design and Testing of

Transmission Modular Restoration Structure Components” and test results should be

compliant with the requirement of IEEE1070-2006.

The ERS structure elements shall be of a robust design to prevent damage during

expected rough field handling during emergency conditions.

11.4.4 Foundation Plate

The foundation plate shall be designed to rest on the ground surface with anchors or metal

stakes to avoid sliding. It shall be made of light weight; high strength material. The base

area of the foundation plate shall be designed to work safely on regular earth bearing

capacity soils (200kpa or more).

11.4.5 Articulated Base

The articulated base shall be of such design that it can be fixed on the foundation plate. It

shall allow assembly of structures over itself. It shall allow leaning and rotation in all

directions. It shall minimize column eccentricity and eliminate torsion loading on

structures due to its rotational capability. It shall be made of lightweight, high strength

material.

11.4.6 Guy plates and Box sections

The design of Guy plates shall be such that they shall allow attachment of insulators and

guy wires to the structure. They shall have predetermined holes to allow attachment of

insulators and guy wires. Depending upon the requirement, the angle of guy plates shall

be 0/0, 0/45 or 45/45. It shall be made of light weight, high strength material. Castings are

not allowed. The guy plates shall transmit a horizontal load from one side of the plate to

the other side without loading the ERS tower.

Box section shall be of such design that it allows attachment/mounting of insulators and

guy wires to the structure. They shall be assembled between column structures and shall

have predetermined holes on sides to allow attachment of insulators and guy wires. It shall

be made of light weight, high strength material. The guy plates and box sections shall be

geometrically in accordance with IEEE Std. 1070-2006 “IEEE Guide for the Design and

Testing of Transmission Modular Restoration Structure Components”,



11.4.7 Anchoring assembly

Depending on the prevailing soil conditions, different anchoring arrangements shall be

required. The suitable anchoring assembly for following type of soils shall be supplied:

i) For soft soils.

ii) For soft rock soils. iii) For hard rock soils.

iv) For poor soils.

11.4.8 Insulators

The ERS shall be equipped with all necessary insulators fittings and accessories necessary

for attaching the conductor sizes ACSR MOOSE, ACSR ZEBRA, ACSR BISON and

ACSR BEAR.

Every insulator body shall have a durable and legible trade mark and year of manufacture

as well as the rated combined mechanical strength in kilo Newton.

The insulators shall be of the modular design so as to use for all required voltages

(400 kV, 220 kV and 132 kV) using the same size insulators in series.

11.4.9 Guy Wire and Grips

All guy wire shall conform to ASTM-A474. The guy wire shall have a minimum breaking

strength of (134kN). Guy wire shall be 19 strands for flexibility. All guy wire shall be

shipped on steel spools.

All guy wires shall be provided with compatible helical preformed grips for attachment to

anchor rods and guy wire thimbles. These preformed grips shall have a minimum

ultimate strength of (134kN).

11.4.10 Construction Tools and Equipment

The supplier shall offer 2 (two) sets of all the necessary construction tools, hand tools and

equipment required for assembly and erection of the ERS towers and lifting of the

conductors. The items/tools to be supplied shall include but not be limited to the

tools/items described as follows:

Each set of construction tools shall consist of the following:

(i) One (1) gin poles made from aluminum alloy will be provided. The gin pole

shall be supported on one corner of a column section and allow lifting of up to

450kg. to the top of the structure. The gin pole shall be suitable for simultaneous

lifting a 21 foot column section and a Box section as described in Figures 1 and 5

of IEEE Standard 1070. All necessary snatch blocks and rigging ropes will be

supplied with the gin pole. All ropes shall be a minimum 5/8” polyester rope.

The gin pole shall have a swivel base for initially tilted up with a hand winch,

with the base of the gin pole pivoting on the foundation plate. After the initial

tilt up and placement of the gimbal and first column section, no additional guy

lines shall be needed and the gin pole shall be self-supporting on the emergency

restoration structure. The gin pole shall have a davit arm to keep loads clear of

the structure while being raised by a capstan hydraulic power unit and low

friction bushings for rotation of the load. A slider shall clamp to the corner



members of the emergency restoration structure and allow the gin pole to be

raised on the structure using a pulley and the capstan wench.

(ii) A quantity of six (6), 2-ton Tirfor grip hoist will be provided with 150 foot of

7/16” (11.5mm) wire rope. Forged safety hooks shall be provided on both ends for

the Tirfor grip hoist body and for the 7/16” wire rope.

(iii) One (1) ½ ton hydraulic capstan winch with foot pedals shall be provided with

each gin pole. This capstan shall be capable of being powered by the same

hydraulic power unit used to install the soil anchors. The capstan shall be

mounted on a plate that can be anchored to the ground.

(iv) A quantity of twelve (12), 15” long reversible ratchet for hand installation of

ERS bolts as described in IEEE Standard 1070 Section 3.1. The reversible

ratchet shall be made of forged material and provided with a ½” square drive,

15/16” deep socket in order to provide additional clearance for tightening the nut.

A quantity of twelve (12), forged closed box wrenches with a drift pin will also

be provided as an assembly tool.

(v) A quantity of six (6), three (3) ton reversible chain hoists will be provided for

tensioning of guy wires and conductor. Forged safety hooks shall be provided

on the reversible chain hoist. The hook throat openings shall be a minimum of 1

½” square drive, 15/16” deep socket in order to provide additional clearance for

tightening the nut. A quantity of twelve (12), forged closed box wrenches with a

drift pin will also be provided as an assembly tool.

(vi) A quantity of twelve (12), ferrous pulling eyes that attach to the anchor rods and

allow placement of safety hooks for either the 3 ton chain hoist or the 2 ton Tirfor

grip hoist shall be provided.

(vii) A quantity of sixteen (16), automatic wire grips suitable for gripping the 9/16

x 19 strand guy wire shall be provided. The grips shall be made of

forged steel and have a bail suitable for attachment of the 3 ton chain hoist safety

hook.

(viii) A quantity of four (4) sets of lineman safety harness and fall arrest and twenty (20)

safety helmets.

(ix) A quantity of two (2), ten foot (3m), 5/8m (16 mm) diameter double loop 6 x 37

steel wire rope slings shall be provided. These slings shall have a loop eye swaged

at both ends and have an ultimate strength of (134kN). A quantity of two (20, ten

foot (3m), 3in, wide (76mm), two ply nylon slings shall be provided for lifting

purposes. The slings shall have a twisted eye at both ends and have a rated capacity

of (42kN) when loaded vertically. A quantity of eight (8), 6 ft(1.8m) long, round

endless slings, with a rated capacity of (24kN) when loaded vertically, shall be

provided for temporary guying of this structure.

(x) A quantity of three (3), aluminum conductor lifting hooks shall be provided. These

lifting hooks shall be made from 6061-T651 aluminum and shall a minimum

ultimate strength of (45kN).

(xi) A quantity of six (6) light weight aluminum Anchor Construction

(xii) Yokes that allow attachment of up to three Tirfor grip hosts, Chain hoists and / or

ropes to one pulling eye and anchor rod will also be supplied.

(xiii) One (1), self contained 6 ton hydraulic wire cutter shall be provided. This self

contained hydraulic cutter shall be capable of not only cutting the 9/16 x 19 strand

guy wire but also the ACSR conductor and the overhead static wire.

Tools shall be supplied to fully assemble the tower without the need to run around for a

missing wrench. i- Working platform for clipping the conductors into post

insulator assemblies.



ii- Sliding gin pole capable of being attached to corner rails of the column

section.

iii- Ball-joint gin pole capable of rotating at least 20 meters of horizontal

mast section assembly.

iv- Tirefor grip hoist – 2.0 tons or more with at least 45m of wire rope of

suitable capacity. v-Sliding linemen safety devices capable of being attached to corner rails

of the column section.

vi- All necessary snatch blocks and ropes shall be supplied with the gin pole vii-

Alignment tool, Resting platform, pionjar, portable winch, fall

arrestor...etc

Tools shall be supplied to fully assemble the tower without the need to run around

for a missing wrench.

11.4.11 Containers for ERS

Required number of 20 foot (6M.) ocean cargo storage containers with container

storage system, using racks, bins, shelves and protective tubes for insulators with clear

identification shall be supplied for storage of complete ERS components/material with

associated tools and tackles. These containers shall be outfitted for holding all of the hardware, insulators, guy plates, guy and anchor accessories, tools (including the gin pole) and nuts and bolts. The insulators shall be held in PVC conduit tubes in order to protect them from adjacent insulators. All hardware and nuts and bolts shall be stored in ferrous metal wire containers. There shall be easy access to the containers and easy access to the parts in the containers. The 20 foot ocean cargo storage container shall be lockable to prevent loss. All ERS components with the exception of the large ERS structure components and guy wire shall be stored in these 20 foot containers.

11.4.12 Computer Software

The computer software must have a precise capability for designing and

analyzing any configurations of any modular aluminium towers in any weather criteria and

for any transmission line parameters. It must be able to handle both linear and non-linear

analysis.

The program shall be accompanied by a thorough instruction manual that explains

the theory used and gives examples for each type of structure.

The program should be a recognized standard program in the industry (i.e. PLS-

CADD, PLS‐POLE/LW+MAST) and must not proprietary to one supplier.

The computer program shall be copied 4 minimum (four) times as deemed necessary

by the asset owner, for its own use, without incurring additional licensing fees. Up-

gradation of computer program, if any should be furnished free of cost for

five years.

11.5 OTHER ACCESSORIES AND EQUIPMENT



11.5.1 Laptop

A Laptop built with rugged features and pre-loaded with Windows 8 operating system and

most popular, effective & latest version of Antivirus software etc. shall be required

with ERS. Laptop generally boasting a 2.4GHz Core i7-3630QM quad-core

processor, 750GB hybrid storage, 4GB/8GB of RAM (upgradeable to 24GB), GeForce

GTX 660M discrete graphics with 2GB of GDDR5, a DVD burner, HDMI, and plus

USB 3.0, features a built-in wireless LAN for speedy Web access or other latest

features would be preferred. 100% genuine leather laptop bag with trolley shall also be

provided with laptop for safety during transit & handling.

11.5.2 Walkiy-Talky

Four (4) sets of Water, shock, vibration & impact proof Walky-Talky with working

frequency range 29 - 42 / 35 -50 / 136 -174 / 330 - 400 / 403 - 470 / 450 – 527 MHz with

16 Channel Capacity and having Battery backup of 10 to 12 Hrs (preferably Li-Ion

Battery) shall be provided with the ERS for conveying communications among the

various groups of personnel working with ERS during any emergency.

11.5.3 Portable Diesel Generator Set:

Energy efficient and sturdy in construction Diesel Generator set confirming to

International standards and capable of taking load of 10 to 12 KW shall be provided along

with the ERS for illumination at site while using ERS during any emergency.

11.5.4 GPS Receiver:

Two (2) Sets of 2.2’ monochrome display, high-sensitivity WAAS-enabled GPS receiver

with Hot Fix and GLONASS support, worldwide basemap, supporting paperless

geocaching, USB interface, rugged & waterproof shall also be required for GPS based

survey during any emergency to fulfill the requirements of computer based program for

ERS.

11.5.5 Total Station Surveying Equipment :

Two (2) Total Station having latest features, speed, accuracy, ease-of-use and reliability

will be provided. The specifications given hereunder are mentioned for a guideline as per

technical particulars available with NEA, however, the Total Station with upgraded

features/latest versions other than the specified under will be preferred –

SPECIFICATIONS:

a. Telescope

i. Image - Erect

ii. Magnification ≥30X

iii. Field of view ≥22m @ 1000 m

iv. Minimum focus distance ≤2.0 m

v. Resolving power ≤2.5”

b. Angle measurement

i. Tilt compensation method – dual axis ii.

Tilt compensation range ≥3”



iii. Angle accuracy ≤2” horizontal and vertical

iv. Displayed resolution (Least count) ≤1”

c. Distance measurement

i. Range (20 km visibility) ≥1500 m with 1 prism & ≥3000 m with assembly of 3 prisms.

ii. Accuracy (in static mode) ≤(5 mm+3 ppm of distance)

iii. Resolution (Least count) ≤1 mm

iv. Measurement time ≤5 s

v. Prism –Retro reflective type

d. Optical plummet

i. Magnification ≥2.0 x

ii. Focusing range ≤0.5 to ≥2 m

iii. A small Bull‟s eye Bubble on alidade.

iv. Tow Electronic bubbles 30‟ sensitivity at right angles to each other on display panel.

v. One Circular Bubble on Tribrach.

e. Key board and display – Alpha Numeric keyboard on both sides (identical). Display:1/4, VGA (320*240 pixels), graphic LCD, colour, illumination, Touch screen Keyboard: (function keys, alphanumeric keys), Angle display: 360° „ “, 360° decimal. Readable under field light conditions. Marking on keys are clear and non-removable. Graph of entire survey displayed on screen of Total Station with Zoom & Pan facility.

f. Pressure & Temperature sensors – In built Temperature & pressure Sensors for measurement and display of instant atmospheric temperature and pressure in SI system of unit.

g. Accessories – Total station should have following original accessories showing company‟s mark on it in strong carrying case with Data Transfer Cable. Data Transfer Software:

Two rechargeable Batteries, One Charger, One CD containing Instruction Manual. Two Single prism with Target Plate and one wooden stand Range, Two pole, Two display, Two Detachable Tribrach, lens cover set, cleaning brush, cover of durable plastic, shock absorbing carrying case with shoulder strap etc in complete.

h. Data storage (with pc-software for data retrieval, presentation and archiving)

• Capacity ≥10000 points on board memory or more

• SD Card/CF card slot with 256 MB or more

• RS232/USB Interface

i. Focusing Mode:

Three Focusing Mode viz. a) Auto Focus mode

b) Power Focus mode c) Manual Focus mode

j. Physical

i. Weight ≤10 kg

ii. Temperature range ≤0 to ≥55 ° C fully operational



iii. Humidity 0 to ≥90% RH

iv. Protection splash waterproof and dustproof

k. Power

i. Batteries Li-ion rechargeable, no memory effect, during changing of batteries.

ii. Capacity ≥4 hours of continuous measuring

iii. Battery charger, adaptor and cables iv. Recharge time ≤ 2 hours

v. Power supply 220 VAC ±25%; 47 to 53Hz vi. Operating temperature 0 to 55° C vii. Humidity 0 to≥90% RH

l. Other features

i. Tri axis Compensator (in addition to dual axis correction in the (X) and (Y) direction, mechanical error in the instrument is corrected).

ii. Range under Normal Conditions:-

• Single Prism: 5000 to 7000m or more

• Distance Accuracy in Prism Mode:

a) Up to 10 meters: + (3mm+2ppmxD) mm

b) From 10 meters: + 2mm+2ppmxD)mm

• Distance Accuracy in Reflector less Mode: Up to 300 meters:+(5mm+2ppmXD)mm

m. Probable Quantity: - 1 no.

Conditions and requirements :

• The total station shall be of such a design that it functions reliably and accurately under the prevailing environmental and operational conditions.

• The total station should be able to work efficiently within the temperature range 0° C to + 55° C

• Can measure Distance without Reflector 300 to 500 meter to a 90% reflective object (in good condition).

• The total station shall be easy to operate and maintain.

• The total station shall have all the latest technology of Absolute Encoders.

• The total station shall be supplied with the accessories as needed for effective deployment.

• All materials of the total station exterior shall be non-corrosive.

• All enclosures, cables and connectors shall be sturdy and water resistant.

• The total station shall be a rugged design that can cope with the prevailing shock and vibration as experienced in surveying operations and transport by jeep in rough terrain.

• The total station shall have an expected technical lifetime of not less than 10 years.

• Operator‟s and technical manuals, related to the type and model of the total station and the accessories shall be part of the delivery.



• Power consumption shall be small, to be derived from batteries integrated and/or External batteries.

• The batteries shall be rechargeable and assembled in packages

• The connectors and electrical cables associated with the total station shall be reliable and sturdy.

• The total station shall have Visible Laser Pointer.

• Date & Time is recorded while modifying or creating a file.

• On Board pre-loaded graphical software Power Topo Lite or

equivalent including Area Perimeter, Volume (Cut/fill) and Licensed copy of Auto Plotter Civil Software should invariably be part of the supply. In built road design function.

• The total station shall comprise.

a. Theodolite with integrated laser distance meter, tilt compensation, digital controller with keypad and display, supporting data storage.

b. Data retrieval and communication unit . b. Tripod for the total station. c. Prism poles with associated tripods for prism assemblies.

• The laser output power shall be eye safe.

• Operational training shall be part of the delivery.

11.5.6 Tripod with Chain Pulley Block System having Capacity to lift 10 MT Load

The tripod stand shall be made of heavy duty G.I. pipe. The height of tripod shall be 6 meter. It should be provided with cast iron cones and steel disc on bottom. The safe working load capacity of tripod shall be 10 tonnes with factor of safety 2. Chain pulley block shall be of light weight robust in construction and incorporate highly efficient tripple spur gear reduction. The body of chain pulley block shall be made of pressed steel with weldless construction. Hooks shall be made of High Tensile Forged steel conforming to I.S. 8610 which can rotate and swivel freely. Load wheel shall be accurately machined, suitably made and heat treated. Brake shall be multiple threaded screw and friction disc type self actuating load break type. All load bearings/gear shall be made from special alloy steel precision machine cut case hardened and treated for rust prevention. The chain pulley block shall be of 10 tonne working with capacity having spur gear and the lift shall be of 3 meters.

11.5.7 Motorised Capstan Hoist having lifting/pulling capacity of 10 MT

Motorised capstan hoist should be versatile of 10 tone capacity suitable for overhead and underground lifting and pulling applications like Raising/shifting Transformers, stringing and tensioning of conductor & earthwire, hoisting heavy insulators, setting utility poles, pulling underground cable. The unit should be small & compact but rugged in construction and lightweight for making it perfect for use in remote and limited access areas. It should operate with 12 Volt d.c. (off Truck Battery) and should have other features like friction less bearings, worm gear reduction for positive load holding, Dynamic braking for instant stopping, high speed gears, upside-down Mounting, variable speed, full power



reversible, Free-wheeling clutch, Low voltage 10‟ pendant control, limit switch, alternate drums, high-capacity cable drum, Steel capstan drum with larger radius at load-line wrap and zinc- plated rope surface Hand Crank. The unit should have long lift with the facility of truck/pole mounting, swivel mounting and receiver hitch mounting.

11.6 Inspection and Test

The NEA or the party assigned by NEA shall have the right to inspect and witness

factory tests of the equipment included in this Contract. The contractor is required to

provide all facilities to enable the employer’s representative to carry out inspection witness

the test. .

At least 30 days notice of the date, time and place of all tests shall be given to the

Employer so that arrangements can be made to have the test witnessed.

Prior to the tests the Contractor shall submit an outline of the procedures and tests in its

plans, to demonstrate fulfillment of the requirements specified in subsequent sections of

the detailed technical specification.

The ERS towers, accessories and fittings shall be tested with the relevant IEC

standard as well as IEEE guide (IEC 61284 and IEEE 1070-2006)

11.7 Training to the Engineers/Technicians

- The bidder shall provide a One week long training to Four (4) engineers in

analyzing the configurations of modular aluminium towers in local weather conditions

and for the given transmission line parameters in the Employer premises including

training on computer software.

- The bidder shall also provide a one week long hands-on training in the field

conditions to twenty (20) field staff in the installation of the ERS at purchaser's

premises. The training should cove assembling, erection, dismantling, storage and

maintenance of ERS and computer software training. Special emphasis shall be given

to anchoring, assembling of modular structures, fixing of foundation plates, erecting of

structures on the foundation, guying the tower and stringing of conductor and the

specific instructions for installation of ERS using Gin Pole, crane if there are shall be

given.

- The bidder shall also provide a one week long training to the (2) Engineers in

complete operation of the total station surveying equipment at purchaser's

premises.

11.8 Drawings and Documentations

- All drawings submitted by the supplier including those submitted at the time of bid

shall be in sufficient detail to indicate the type, size, arrangement, dimensions, material

description, bill of materials, weight of each component, etc.



- Each drawing submitted by the supplier shall be clearly marked with the name

of the purchaser, the unit designation, the specification title and the name of the

project. All titles, notes, markings and writings on the drawing shall be in English. All

dimensions should be to the scale and in metric units.

- The supplier shall provide comprehensive transportation, erection, storage and

maintenance manuals along with guidelines.

11.9 Schedule of Guaranteed Characteristics For Modular Emergency Restoration System

With Accessories

The schedules must be filled in by the

bidder No Description Requirement Bidder’s Offer

1 ERS structure Model/Type reference number

Modular, all components to be mutually

compatible

Made of high strength aluminum, should

be of one common length and should be

interchangeable

Maximum length of column section not

more than 4.2 meter

Should be able to withstand compression

forces as outlined in the test procedure of

IEEE 1070-2006

Should be able to withstand bending

forces of as outlined in the test procedure

of IEEE 1070-2006

Should be able to withstand torsion forces

of as outlined in the test procedure of

IEEE 1070-2006

Dimension design and tolerances as per

recommended in IEEE 1070-2006 or

equivalent to meet the request as per

clause 4 of the technical Specification

Maximum weight of ERS tower sections

200kg

2 Strength factor to be used

for each tower member for

design

Steel guy wire 65%

Guy strain insulators 65%

Anchors 50%

Hardware (turnbuckle,

shackle, chain link. etc)

60%

Plates and metal rods

(aluminum or steel)

60%

Guy plates and simple

structural elements

60%

No Description Requirement Bidder’s Offer

3 Guy Plates Model/Type reference number

The design consideration should conform

to those defined in IEEE 1070-2006

4 Bolts, nuts and washers Model/Type reference number

Should be hot-dip galvanized



Ultimate strength bending testing should

be as per those defined in IEEE 1070-

2006

Ultimate strength to be pulled testing

should be as per those defined in IEEE

1070-2006

5 Construction Tools and

equipments

As per clause 11.4.10 of the technical

Specification

6 Containers of ERS As per clause 11.4.11 of the technical

Specification

7 Computer Software As per clause 11.4.12 of the technical

Specification

8 Training: Field training on

the assembly, erection,

dismantling, etc of ERS

and training on Computer

Software

As per clause 11.7 of the technical

Specification

Note :- The filled guaranteed data for ERS should be proven by attaching the

catalogue of the proposed type of ERS MATERIAL REQUIREMENT FOR ONE COMPLETE SET OF ERS

ERS Structure Components

Sl.

No.

Description

Quantity

1 2 3

1.0 ERS Towers mast sections including bolts & nuts as

per requirement to build all of the following:

1.1 ERS Suspension / Running angle Tower and Tension - 3 phase including guy plates and box sections (approx. 48m height

6

2.0 Articulated base /(gimbal) 6

3.0 Foundation / Base Plates including stakes as per

3.1 For ERS Tower

(i) Normal soil 6 (ii) Low bearing capacity soil 3

4.0 ERS computer programs as per section

11.4.12

1 Set

5.0 ERS On site training as per section

11.7



6.0 Conductor Hardware fittings for following type of

arrangement of insulator string assembly:

6.1 Hardware fittings including end attachment, yoke plates,

suspension clamps, extension links, turnbuckles,

corona/grading rings other fittings & components as per requirement for Horizontal Vee

19

6.2 Hardware fittings including end attachment, strain

clamps, extension links, turnbuckles, corona/grading

rings other fittings & components as per requirement for

two Double tension insulator String assembly and one

jumper assembly.

7

11.5.1 Polymer Insulators for Emergency Restoration System

Quantity indicated above is for complete insulator assemblies and not of individual

insulator modules. Further, the insulator assemblies shall be adoptable for restoration

of 400KV, 220KV and 132KV lines.

11.6 Guy Assemblies for Emergency Restoration System

Sl. No.

Description

Quantity

1.0 Guys & guy hardwares

Sl. No.

Description

Quantity

7.0 Earthwire/OPGW fittings

7.1 Earthwire/OPGW Suspension assembly including clamp,

fittings & components as required

7

7.2 Earthwire/OPGW tension/dead-end assembly including

strain/dead-end clamp, fittings & components as required

5

8.0 Insulator Strings assembly

8.1 Modular Composite longrod suspension insulator (160 kN) 40

8.2 Modular Composite longrod post insulator ( minm 90mm

core dia, 120 kN tensile strength, 90 kN compressive

strength)for 400KV lines.

20



1.1 High strength galvanised steel guy wire (14.3 mm dia,

minm 134 kN UTS, standard length 100 m)

150

1.2 Guy wire thimble 300

1.3 Preformed guy grip 300

1.4 Guy hardware including turnbuckle & anchor shackles, as per requirement

80

2.0 Guy Insulators

2.1 Composite guy strain insulator / insulating rod (134 kN tensile strength) alongwith suitable end fittings

100



11.7 Anchor Assemblies for Emergency Restoration System

Sl. Description Quantity

1.0 Anchor Assemblies (min. 150 kN ultimate strength)

including guy adaptor, extension rod

1.1 Cross plate (2 nos. 600 mm x 300 mm) or eqvt.

anchor assy. for normal soil (min anchor rod length

4.25m)

150

1.2 Manta ray MR-1 (177mmx368 mm) or eqvt. Anchor

assy. for normal soil (min anchor rod length with

extension rod 4.25m) or qvt.

150

1.3 Triple helix (250mm-300mm-350mm) anchor assy. for

loose/marshy soils (minm anchor rod length 4.25m)

150

1.5 Rock anchor (55mm anchor dia) assy. (minm anchor

length 3.1m) or eqvt.

150

11.7.1.1 Construction tools for Emergency Restoration System (in accordance with section

3.03.07)

Item Description Quantity

1. Assembly and erection tool set 2

11.8 Anchor Installation Tool Sets


1. Anchor Installation Tool Set and HPU as per section 11.4.10.

1

2. Normal /average Anchor tool set as per section 11.4.10 1

3. Marsh Anchor Installation Tool set as per section 11.4.10

1

4. Rock Anchor Drill Tool set as per section 11.4.10 1



11.9 Storage Container for Emergency Restoration System


1. 20 feet containers for storage of all ERS

components/ material as well as for transportation of the same to

restoration site. The containers shall have suitable stacking arrangement

for storage & provision (sliding stacks or alternate arrangements) for

easy access & removal of material from stacks. The containers shall be

such that these can be loaded on separate trucks or flat bed trailers for

transportation. The containers supplied shall be suitable for indoor

storage & outdoor storage.

As required